For people who speak many languages, there's something special about their native tongue

A new study of people who speak many languages has found that there is something special about how the brain processes their native language.

In the brains of these polyglots -- people who speak five or more languages -- the same language regions light up when they listen to any of the languages that they speak. In general, this network responds more strongly to languages in which the speaker is more proficient, with one notable exception: the speaker's native language. When listening to one's native language, language network activity drops off significantly.

The findings suggest there is something unique about the first language one acquires, which allows the brain to process it with minimal effort, the researchers say.

"Something makes it a little bit easier to process -- maybe it's that you've spent more time using that language -- and you get a dip in activity for the native language compared to other languages that you speak proficiently," says Evelina Fedorenko, an associate professor of neuroscience at MIT, a member of MIT's McGovern Institute for Brain Research, and the senior author of the study.

Saima Malik-Moraleda, a graduate student in the Speech and Hearing Bioscience and Technology Program at Harvard University, and Olessia Jouravlev, a former MIT postdoc who is now an associate professor at Carleton University, are the lead authors of the paper, which appears today in the journal Cerebral Cortex.

Many languages, one network

The brain's language processing network, located primarily in the left hemisphere, includes regions in the frontal and temporal lobes. In a 2021 study, Fedorenko's lab found that in the brains of polyglots, the language network was less active when listening to their native language than the language networks of people who speak only one language.

In the new study, the researchers wanted to expand on that finding and explore what happens in the brains of polyglots as they listen to languages in which they have varying levels of proficiency. Studying polyglots can help researchers learn more about the functions of the language network, and how languages learned later in life might be represented differently than a native language or languages.

"With polyglots, you can do all of the comparisons within one person. You have languages that vary along a continuum, and you can try to see how the brain modulates responses as a function of proficiency," Fedorenko says.

For the study, the researchers recruited 34 polyglots, each of whom had at least some degree of proficiency in five or more languages but were not bilingual or multilingual from infancy. Sixteen of the participants spoke 10 or more languages, including one who spoke 54 languages with at least some proficiency.

Each participant was scanned with functional magnetic resonance imaging (fMRI) as they listened to passages read in eight different languages. These included their native language, a language they were highly proficient in, a language they were moderately proficient in, and a language in which they described themselves as having low proficiency.

They were also scanned while listening to four languages they didn't speak at all. Two of these were languages from the same family (such as Romance languages) as a language they could speak, and two were languages completely unrelated to any languages they spoke.

The passages used for the study came from two different sources, which the researchers had previously developed for other language studies. One was a set of Bible stories recorded in many different languages, and the other consisted of passages from "Alice in Wonderland" translated into many languages.

Brain scans revealed that the language network lit up the most when participants listened to languages in which they were the most proficient. However, that did not hold true for the participants' native languages, which activated the language network much less than non-native languages in which they had similar proficiency. This suggests that people are so proficient in their native language that the language network doesn't need to work very hard to interpret it.

"As you increase proficiency, you can engage linguistic computations to a greater extent, so you get these progressively stronger responses. But then if you compare a really high-proficiency language and a native language, it may be that the native language is just a little bit easier, possibly because you've had more experience with it," Fedorenko says.

Brain engagement

The researchers saw a similar phenomenon when polyglots listened to languages that they don't speak: Their language network was more engaged when listening to languages related to a language that they could understand, than compared to listening to completely unfamiliar languages.

"Here we're getting a hint that the response in the language network scales up with how much you understand from the input," Malik-Moraleda says. "We didn't quantify the level of understanding here, but in the future we're planning to evaluate how much people are truly understanding the passages that they're listening to, and then see how that relates to the activation."

The researchers also found that a brain network known as the multiple demand network, which turns on whenever the brain is performing a cognitively demanding task, also becomes activated when listening to languages other than one's native language.

"What we're seeing here is that the language regions are engaged when we process all these languages, and then there's this other network that comes in for non-native languages to help you out because it's a harder task," Malik-Moraleda says.

In this study, most of the polyglots began studying their non-native languages as teenagers or adults, but in future work, the researchers hope to study people who learned multiple languages from a very young age. They also plan to study people who learned one language from infancy but moved to the United States at a very young age and began speaking English as their dominant language, while becoming less proficient in their native language, to help disentangle the effects of proficiency versus age of acquisition on brain responses.

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Great apes playfully tease each other

Babies playfully tease others as young as eight months of age. Since language is not required for this behavior, similar kinds of playful teasing might be present in non-human animals. Now cognitive biologists and primatologists from the University of California Los Angeles (UCLA, US), the Max Planck Institute of Animal Behavior (MPI-AB, Germany), Indiana University (IU, US), and the University of California San Diego (UCSD, US) have documented playful teasing in four species of great apes. Like joking behavior in humans, ape teasing is provocative, persistent, and includes elements of surprise and play. Because all four great ape species used playful teasing, it is likely that the prerequisites for humor evolved in the human lineage at least 13 million years ago.

Joking is an important part of human interaction that draws on social intelligence, an ability to anticipate future actions, and an ability to recognize and appreciate the violation of others' expectations.

Teasing has much in common with joking, and playful teasing may be seen as a cognitive precursor to joking.

The first forms of playful teasing in humans emerge even before babies say their first words, as early as eight months of age.

The earliest forms of teasing are repetitive provocations often involving surprise.

Infants tease their parents by playfully offering and withdrawing objects, violating social rules (so-called provocative non-compliance), and disrupting others' activities.

In a study recently published in the Proceedings of the Royal Society B, scientists from the University of California Los Angeles, the Max Planck Institute of Animal Behavior, Indiana University, and the University of California San Diego(Isabelle Laumer, Sasha Winkler, Federico Rossano, and Erica Cartmill) report evidence of playful teasing in the four great ape species: orangutans, chimpanzees, bonobos and gorillas.

"Great apes are excellent candidates for playful teasing, as they are closely related to us, engage in social play, show laughter and display relatively sophisticated understandings of others' expectations," says Isabelle Laumer (UCLA/MPI-AB) a post-doctoral researcher and the first author of the study.

The team analyzed spontaneous social interactions that appeared to be playful, mildly harassing, or provocative.

During these interactions, the researchers observed the teaser's actions, bodily movements, facial expressions, and how the targets of the teasing responded in turn.

They also assessed the teaser's intentionality by looking for evidence that the behavior was directed at a specific target, that it persisted or intensified, and that teasers waited for a response from the target.

The researchers found that orangutans, chimpanzees, bonobos and gorillas all engaged in intentionally provocative behavior, frequently accompanied by characteristics of play.

They identified 18 distinct teasing behaviors. Many of these behaviors appeared to be used to provoke a response, or at least to attract the target's attention.

"It was common for teasers to repeatedly wave or swing a body part or object in the middle of the target's field of vision, hit or poke them, stare closely at their face, disrupt their movements, pull on their hair or perform other behaviors that were extremely difficult for the target to ignore," explains UCLA and IU professor Erica Cartmill, senior author of the study.

Although playful teasing took many forms, the authors note that it differed from play in several ways.

"Playful teasing in great apes is one-sided, very much coming from the teaser often throughout the entire interaction and rarely reciprocated," explains Cartmill.

"The animals also rarely use play signals like the primate 'playface', which is similar to what we would call a smile, or 'hold' gestures that signal their intent to play."

Playful teasing mainly occurred when apes were relaxed, and shared similarities with behaviors in humans.

"Similar to teasing in children, ape playful teasing involves one-sided provocation, response waiting in which the teaser looks towards the target's face directly after a teasing action, repetition, and elements of surprise," Laumer explains.

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Can we decode the language of our primate cousins?

Are we able to differentiate between the vocal emissions of certain primates? A team from the University of Geneva (UNIGE) asked volunteers to categorise the vocalisations of three species of great apes (Hominidae) and humans. During each exposure to these ''onomatopoeia'', brain activity was measured. Unlike previous studies, the scientists reveal that phylogenetic proximity -- or kinship -- is not the only factor influencing our ability to identify these sounds. Acoustic proximity -- the type of frequencies emitted -- is also a determining factor. These results show how the human brain has evolved to process the vocal emissions of some of our closest cousins more efficiently. Find out more in the journal Cerebral Cortex Communications.

Our ability to process verbal language is not based solely on semantics, i.e. the meaning and combination of linguistic units.

Other parameters come into play, such as prosody, which includes pauses, accentuation and intonation.

Affective bursts -- ''Aaaah!'' or ''Oh!'' for example -- are also part of this, and we share these with our primate cousins.

They contribute to the meaning and understanding of our vocal communications.

When such a vocal message is emitted, these sounds are processed by the frontal and orbitofrontal regions of our brain.

The function of these two areas is, among other things, to integrate sensory and contextual information leading to a decision.

Are they activated in the same way when we are exposed to the emotional vocalisations of our close cousins the chimpanzees, macaques and bonobos?

Are we able to differentiate between them?

MRI scans with headphones on

A UNIGE team sought to find out by exposing a group of 25 volunteers to various human and simian vocalisations.

''The participants were placed in an MRI scanner and were given headphones.

After a short period of familiarisation with the different types of vocalisations, each participant had to categorise them, i.e. identify to which species they belonged,'' explains Leonardo Ceravolo, senior lecturer at the UNIGE's Faculty of Psychology and Educational Sciences, and first author of the study.

These vocalisations were of the affiliative type, i.e. linked to a positive interaction, or of the agonistic type, i.e. linked to a threat or distress.

The human vocalisations came from databases recorded by actors.

The simian ones came from field recordings made as part of previous research.

This study is the first of its kind to include bonobo vocalisations.

Bonobos, not so close cousins

The results show that for macaque and chimpanzee vocalisations, the frontal and orbitofrontal regions of the participants were activated in a similar way to human vocalisations.

The participants were able to differentiate between them easily.

On the other hand, when confronted with the ''sounds'' of bonobos, also close cousins of humans, the involved cerebral areas were much less activated, and categorisation was at chance level.

''It was thought that kinship between species -- the 'phylogenetic distance' -- was the main parameter for having the ability, or not, to recognise these different vocalisations.

We thought that the closer we were genetically, the more important this ability was,'' explains Didier Grandjean, full professor at the Swiss Center for Affective Sciences and at the UNIGE's Faculty of Psychology and Educational Sciences, who led the study.

''Our results show that a second parameter comes into play: acoustic distance.

The further the dynamics of the acoustic parameters, such as the frequencies used, are from those of humans, the less certain frontal regions are activated.

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Grambank shows the diversity of the world's languages

Linguists have long been interested in language variation. What are common or universal patterns across languages? What limits the possible variation between them? Grambank, the world's largest and most comprehensive database of language structure, enables researchers to answer some of these questions.

Grambank was constructed in an international collaboration between the Max Planck institutes in Leipzig and Nijmegen, the Australian National University, the University of Auckland, Harvard University, Yale University, the University of Turku, Kiel University, Uppsala University, SOAS, the Endangered Languages Documentation Programme, and over a hundred scholars from around the world. Grambank's coverage spans 215 different language families and 101 isolates from all inhabited continents. "The design of the feature questionnaire initially required numerous revisions in order to encompass many of the diverse solutions that languages have evolved to code grammatical properties," says Hedvig Skirgård, who coordinated much of the coding and is the lead author of the study.

Limits on variation

The team settled on 195 grammatical properties, ranging from word order to whether or not a language has gendered pronouns. For instance, many languages have separate pronouns for 'he' and 'she', but some also have male and female versions of 'I' or 'you'. The possible 'design space' would be enormous if grammatical properties were to vary freely. Limits on variation could be related to cognitive principles rooted in memory or learning, rendering some grammatical structures more likely than others. Limits could also be related to historical 'accidents', such as descent from a common language or contact with other languages.

The researchers discovered much greater flexibility in the combination of grammatical features than many theorists have assumed. "Languages are free to vary considerably in quantifiable ways, but not without limits," explains Stephen Levinson, Director emeritus of the Max Planck Institute for Psycholinguistics in Nijmegen and one of the founders of the Grambank project. "A sign of the extraordinary diversity of the 2400 languages in our sample is that only five of them occupy the same location in design space (share the same grammatical properties)."

Languages show much greater similarity to those with a common ancestor than those they are in contact with. "Genealogy generally trumps geography," says Russell Gray, Director of the Department of Linguistic and Cultural Evolution and senior author of the study. "Nevertheless, if processes of linguistic evolution and diversification were run again from the beginning, there would still be some resemblance to what we now have. The constraints of human cognition mean that, while there is a great deal of historical contingency in the organisation of grammatical structures, there are regular patterns as well."

Diversity under threat

"The extraordinary diversity of languages is one of humanity's greatest cultural endowments," concludes Levinson. "This endowment is under threat, especially in some areas such as Northern Australia, and parts of South and Northern America. Without sustained efforts to document and revitalise endangered languages, our linguistic window into human history, cognition and culture will be seriously fragmented."

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Learning to better understand the language of algae

Communication is everything -- and that applies for algae, too. However, their chemical language and its significance in aquatic ecosystems remain largely unknown. A research duo from the Helmholtz Centre for Environmental research (UFZ) and the Plymouth Marine Laboratory (PML) have published a corresponding review in Biological Reviews. This summarizes the current state of knowledge and identifies new approaches for future research in the language of algae and their ecological relationships.

Can algae talk? "Well, although they don't have any mouth or ears, algae still communicate with their own kind and with other organisms in their surroundings. They do this with volatile organic substances they release into the water," says Dr. Patrick Fink, a water ecologist at the UFZ's Magdeburg site. These chemical signals are known as BVOCs (biogenic volatile organic compounds) and are the equivalent of odours in the air with which flowering plants communicate and attract their pollinators. When under attack by parasites, some plant species release odours that attract the parasites' natural enemies to them. "Algae also employ such interactions and protective mechanisms," says Fink. "After all, they are among the oldest organisms on Earth, and chemical communication is the most original form of exchanging information in evolutionary history. However, our knowledge in this area still remains very fragmentary."

Patrick Fink is the corresponding author of the article recently appearing in Biological Reviews, where he has summarized the current status of research in the chemical communication of algae. "For example, we know from laboratory investigations that some species of cyanobacteria keep water fleas at bay by releasing BVOCs in the water. This signal apparently acts as a repellent and has a true added value for the algae, namely that of effective grazing protection," says Fink. In contrast, it is not yet understood why some freshwater algae growing as biofilms on rocks or shellfish shells, for example, release BVOCS on grazing by pond snails. Because: These chemical signals attract more snails. "The pond snails very clearly use the BVOCs to their advantage -- but it remains unknown what function they actually serve for the algae," says Fink. An example from the ocean: A diatom bloom represents a true feast for copepods. This rich offering of nutrients should ensure that their population subsequently grows. However, this is not the case. "Although the copepods are well nourished, their spawn that they carry with them in their egg sack is at serious risk. Because the BVOCS from the diatoms impede cell division and thus disrupt embryonic development," Fink explains "In this way, the diatoms prevent excessive predation on their descendants -- thereby ensuring the preservation of their kind."

The language of algae was first detected in investigations of macroalgae in the early 1970s. "Macroalgae -- such as the bladder wrack also known from the coasts of Germany -- reproduce by releasing gametes into the water. The male and female gametes each release pheromones so that they can also find each other in the vastness of the ocean," explains Dr. Mahasweta Saha, marine chemical ecologist at the Plymouth Marine Laboratory (PML) in Great Britain. "This was the first indication that algae communicate via chemical signals, and that they fulfil important ecological functions."

In their publication, the author duo references the presumably significant effect of BVOCS within aquatic ecosystems, identifies gaps in knowledge and indicates possible future research areas such as coevolutionary processes between signal senders and receivers or the consequences of changes in the environment caused by humans on aquatic ecosystems. "As the primary producers, algae form the basis of life of all aquatic food webs," says Fink. "It is therefore important that we learn to better understand the chemical communication of algae and their basic functional relationships in aquatic ecosystems."

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Properties of 'baby talk' similar across many languages

A study by the University of York and Aarhus University has revealed that baby talk displays similar properties across 36 languages.

'Baby talk' or infant directed speech (IDS) refers to the way caregivers talk to young infants, and generally includes a high-pitched, slow-paced, animated speech.

This spontaneous, automatic and intuitive way of speaking has been studied for decades to understand why human beings communicate in this way with infants and what it might suggest about child development.

The York and Aarhus team addressed the question of whether IDS had a universal quality -- does it, for example, have the same properties in English as it does in other languages? They also addressed whether this changes as the child's grasp on language and speech increases.

Using a meta-analytic method, they examined all previous studies that investigated sound properties of IDS and asked what these revealed about its function in child language development. They found that certain features of IDS, such as pitch, melody, and articulation rates have the same properties across most of the world's languages.

How much caregivers exaggerate the differences between vowel sounds, however, was markedly different across the languages.

Christopher Cox, who led the study and is a joint PhD student at the University of York's Department of Language & Linguistic Science and Aarhus University's Department of Linguistics & Cognitive Science, said: "We use a higher pitch, more melodious phrases, and a slower articulation rate when talking to infants compared to how we talk to adults, and this appears to be the same across most languages.

"In the English language, caregivers typically exaggerate the difference in vowel sounds in infant directed speech, but this seemed to vary across other languages. More work is needed to understand why that is, but we might expect, for example, that speakers of languages with lots of vowels would be more inclined to clarify this speech signal for their children."

Languages that have been studied so far have focused on English and European languages, but to understand more about the instinctive use of IDS and how it helps in child development, the researchers argue more work is needed in understudied, non-Western languages.

The study also showed that IDS changes over time, as infants get a better grasp on language and speech. Most features of IDS gradually become more similar to adult speech style -- such as pitch and speed of delivery -- but other features, such as the high pitch melodic sounds and exaggerated vowels continue into early life.

Associate Professor Riccardo Fusaroli, co-author of the study from Aarhus University, said: "These results really highlight the interactive nature of this speech style, with caregivers providing dynamic and tailored feedback to their children's vocalisations and reacting to infants' changing developmental needs."

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After stroke in an infant's brain, right side of brain compensates for loss of language in left side

A clinical study conducted by researchers at Georgetown University Medical Center found that, for children who had a major stroke to the left hemisphere of their brain within days of their birth, the infant's brain was 'plastic' enough for the right hemisphere to acquire the language abilities ordinarily handled by the left side while also maintaining its own language abilities as well.

The left hemisphere of the brain is normally responsible for sentence processing (understanding words and sentences as we listen to speech). The right hemisphere of the brain is normally responsible for processing the emotion of the voice -- is it happy or sad, angry or calm. This study sought to answer the question "what happens when one of the hemispheres is injured at birth?"

The findings appear in PNAS the week of October 10, 2022.

The participants in this study developed normally during pregnancy. But around birth they had a significant stroke, one that would have debilitating outcomes in adults. In infants, a stroke is much rarer but does happen in roughly one out of every four thousand births.

The researchers studied perinatal arterial ischemic stroke, a type of brain injury occurring around the time of birth in which blood flow is cut off to a part of the brain by a blood clot. The same type of stroke occurs much more commonly in adults. Previous studies of brain injury in infants have included several types of brain injury, but the focus in this study on a specific type of injury enabled the authors to find more consistent effects than in previous work.

"Our most important conclusion is that plasticity in the brain, specifically the ability to reorganize language to the opposite side of the brain, is definitely possible early in life," says Elissa Newport, Ph.D., director of the Center for Brain Plasticity and Recovery at Georgetown Medical Center, professor in the departments of Neurology and Rehabilitation Medicine and first author of this study. "However, this early plasticity for language is restricted to one brain region. The brain is not able to reorganize injured functions just anywhere as more dramatic reorganization is not possible even in early life. This gives us great insights into the regions we might be able to focus on for potential breakthroughs in developing techniques for recovery in adults as well."

The investigators recruited people from across the United States who all had medium to large strokes to the cortex region of their left hemisphere around the time of birth. To assess long-term outcomes in their language abilities, participants were given language tests at 9 to 26 years of age and were compared to their close-in-age healthy siblings. They were also scanned in an MRI to reveal which brain areas were involved in sentence comprehension.

The participants and their healthy siblings all completed the language tasks almost perfectly. The major difference was that the stroke participants processed sentences on the right side of the brain while their siblings processed sentences on the left side. The stroke participants showed a very consistent pattern of language activation in the right hemisphere, regardless of the extent or location of damage from the stroke to the left hemisphere. Only one of the 15 participants, who had the smallest stroke, did not show clear right hemisphere dominant activation.

"It is also notable that many years after their strokes our participants are all such highly functioning adults. Some are honor students and others are working toward or have gotten their master's degrees," says Newport. "Their achievements are remarkable, especially since some of their parents had been told when they were born that their strokes would produce life-long impairments."

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Gestures can improve understanding in language disorders

When words fail, gestures can help to get the message across -- especially for people who have a language disorder. An international research team has now shown that listeners attend the gestures of people with aphasia more often and for much longer than previously thought. This has implications for the use of gestures in speech therapy.

People who suffer from an acquired language disorder due to a brain injury -- for example after a stroke, traumatic brain injury or brain tumor -- often have difficulties communicating with others. Previous research on aphasia indicates that these patients often try to express their needs using hand gestures. It was previously assumed that conversation partners pay relatively little attention to such non-verbal forms of communication -- but this assumption was based on research involving participants without language disorders.

Communicating with gestures

A new study from the University of Zurich, carried out together with researchers from the Netherlands and Japan, looked at whether gestures receive more attention if the verbal communication is impeded by aphasia. The researchers showed healthy volunteers video clips in which people with and without speech disorders described an accident and a shopping experience. As the participants watched the video clips, their eye movements were recorded.

Focus of attention shifts

"Our results show that when people have very severe speaking difficulties and produce less informative speech, their conversation partner is more likely to pay attention to their hand movements and to look longer at their gestures," says Basil Preisig of the Department of Comparative Language Science at UZH. In people who have no limitations in verbal production, hand gestures are granted less attention. Thus, it seems that listeners shift their attention when the speaker has a speech impediment and focus more on the speaker's nonverbal information provided through gestures. "For people with aphasia, it may be worth using gestures more in order to be better understood by the other person," says Preisig.

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Chimpanzees combine calls to form numerous vocal sequences

Compared to the complex use of human language, the way animals communicate with each other appears quite simple. How our language evolved from such a simple system, remains unclear. Researchers from the Max Planck Institutes for Evolutionary Anthropology (MPI-EVA) and for Cognitive and Brain Sciences (MPI-CBS) in Leipzig, Germany, and the CNRS Institute for Cognitive Sciences in Bron, Lyon, France, recorded thousands of vocalisations from wild chimpanzees in Taï, Ivory Coast. They found that the animals produced hundreds of different vocal sequences containing up to ten different call types. The order of calls in these sequences followed some rules, and calls were associated with each other in a structured manner. The researchers will now investigate if this structure may constitute a step towards human syntax and if chimpanzees use these sequences to communicate a wider range of meanings in their complex social environment.

Humans are the only species on earth known to use language. We do this by combining sounds to form words and words to form hierarchically structured sentences. The question, where this extraordinary capacity originates from, still remains to be answered. In order to retrace the evolutionary origins of human language, researchers often use a comparative approach -- they compare the vocal production of other animals, in particular of primates, to those of humans. In contrast to humans, non-human primates often use single calls -referred to as call types -- and rarely combine them with each other to form vocal sequences.

Consequently, vocal communication in non-human primates seems much less complex than human communication. However, human language complexity does not arise from the number of sounds we use when we speak, which is typically bellow 50 different sounds in most languages, but from the way we combine sounds in a structured manner to form words and hierarchically combine these words to form sentences to express an infinite number of meanings. In fact, non-human primates also use up to 38 different calls to communicate, but they rarely combine them with each other. However, since they have so far not been analysed in great detail, we may not have a full picture of the structure and diversity of vocal sequences produced by non-human primates.

Researchers recorded thousands of vocalisations

Researchers at MPI-EVA and MPI-CBS in Leipzig and from the Institute of Cognitive Sciences at the CNRS in Bron, Lyon, France, recorded thousands of vocalisations produced by the members of three groups of wild chimpanzees in the Taï National Park in Ivory Coast. They identified 12 different call types and assessed how chimpanzees combine them to form vocal sequences. "Observing animals in their natural social and ecological environment reveals a previously undiscovered complexity in the ways they communicate," says first author Cédric Girard-Buttoz. "Syntax is a hallmark of human language and in order to elucidate the origin of this human ability it is crucial to understand how non-human primate vocalisations are structured," adds Emiliano Zaccarella, another lead author of the study.

The study shows that chimpanzees communicate with each other using hundreds of different sequences, combining up to ten call types across the whole repertoire. This is the first documentation of such a diversity of vocal production in non-human primates. Furthermore, the researchers show that calls -- in combination with specific other calls -- predictably occurred in certain positions in the sequence, following adjacency rules. These adjacency rules applied also to sequences with three call types.

"Our findings highlight a vocal communication system in chimpanzees that is much more complex and structured than previously thought," says co-author Tatiana Bortolato who recorded the vocalisations in the forest. "This is the first study in a larger project. By studying the rich complexity of the vocal sequences of wild chimpanzees, a socially complex species like humans, we expect to bring fresh insight into understanding where we come from and how our unique language evolved," Catherine Crockford, senior author on the study, points out.

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What do you see when you listen to music?

Are we all imagining the same thing when we listen to music, or are our experiences hopelessly subjective? In other words, is music a truly universal language?

To investigate those questions, an international team of researchers (including a classical pianist, a rock drummer and a concert bassist) asked hundreds of people what stories they imagined when listening to instrumental music. The results appeared recently in the Proceedings of the National Academy of Sciences.

The researchers, led by Princeton's Elizabeth Margulis and Devin McAuley of Michigan State University, discovered that listeners in Michigan and Arkansas imagined very similar scenes, while listeners in China envisioned completely different stories.

"These results paint a more complex picture of music's power," said Margulis, a professor of music who uses theoretical, behavioral and neuroimaging methodologies to investigate the dynamic experience of listeners. "Music can generate remarkably similar stories in listeners' minds, but the degree to which these imagined narratives are shared depends on the degree to which culture is shared across listeners."

The 622 participants came from three regions across two continents: two suburban college towns in middle America -- one in Arkansas and the other in Michigan -- and a group from Dimen, a village in rural China where the primary language is Dong, a tonal language not related to Mandarin, and where the residents have little access to Western media.

All three groups of listeners -- in Arkansas, Michigan and Dimen -- heard the same 32 musical stimuli: 60-second snippets of instrumental music, half from Western music and half from Chinese music, all without lyrics. After each musical excerpt, they provided free-response descriptions of the stories they envisioned while they listened.

The results were striking. Listeners in Arkansas and Michigan described very similar stories, often using the same words, while the Dimen listeners envisioned stories that were similar to each other but very different from those of American listeners.

For example, a musical passage identified only as W9 brought to mind a sunrise over a forest, with animals waking and birds chirping for American listeners, while those in Dimen pictured a man blowing a leaf on a mountain, singing a song to his beloved. For musical passage C16, Arkansas and Michigan listeners described a cowboy, sitting alone in the desert sun, looking out over an empty town; participants in Dimen imagined a man in ancient times sorrowfully contemplating the loss of his beloved.

Quantifying similarities between free-response stories required huge amounts of natural language data processing. The tools and strategies that they developed will be useful in future studies, said Margulis, who is also the director of Princeton's Music Cognition lab. "Being able to map out these semantic overlaps, using tools from natural language processing, is exciting and very promising for future studies that, like this one, straddle the border between the humanities and the sciences."

"It's amazing," said co-author Benjamin Kubit, a drummer and a postdoctoral research associate previously in the Princeton Neuroscience Institute and now in the Department of Music. "You can take two random people who grew up in a similar environment, have them listen to a song they haven't heard before, ask them to imagine a narrative, and you'll find similarities. However, if those two people don't share a culture or geographical location, you won't see that same kind of similarity in experience. So while we imagine music can bring people together, the opposite can also be true -- it can distinguish between sets of people with a different background or culture."

Though the researchers had carefully ensured that the pieces they chose had never appeared in a movie soundtrack or any other setting that would prescribe visuals, the same music sparked very similar visuals in hundreds of listeners -- unless they had grown up in a different cultural context.

"It's stunning to me that some of these visceral, hard-to-articulate, imagined responses we have to music can actually be widely shared," said Margulis. "There's something about that that's really puzzling and compelling, especially because the way we encounter music in 2022 is often solitary, over headphones. But it turns out, it's still a shared experience, almost like a shared dream. I find it really surprising and fascinating -- with the caveat, of course, that it's not universally shared, but depends on a common set of cultural experiences."

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Can artificial intelligence reveal why languages change over time?

The way we speak today isn't the way that people talked thousands -- or even hundreds -- of years ago. William Shakespeare's line, "to thine own self be true," is today's "be yourself." New speakers, ideas, and technologies all seem to play a role in shifting the ways we communicate with each other, but linguists don't always agree on how and why languages change. Now, a new study of American Sign Language adds support to one potential reason: sometimes, we just want to make our lives a little easier.

Deaf studies scholar Naomi Caselli and a team of researchers found that American Sign Language (ASL) signs that are challenging to perceive -- those that are rare or have uncommon handshapes -- are made closer to the signer's face, where people often look during sign perception. By contrast, common ones, and those with more routine handshapes, are made further away from the face, in the perceiver's peripheral vision. Caselli, a Boston University Wheelock College of Education & Human Development assistant professor, says the findings suggest that ASL has evolved to be easier for people to recognize signs. The results were published in Cognition.

"Every time we use a word, it changes just a little bit," says Caselli, who's also codirector of the BU Rafik B. Hariri Institute for Computing and Computational Science & Engineering's AI and Education Initiative. "Over long periods of time, words with uncommon handshapes have evolved to be produced closer to the face and, therefore, are easier for the perceiver to see and recognize."

Although studying the evolution of language is complex, says Caselli, "you can make predictions about how languages might change over time, and test those predictions with a current snapshot of the language."

With researchers from Syracuse University and Rochester Institute of Technology, she looked at the evolution of ASL with help from an artificial intelligence (AI) tool that analyzed videos of more than 2,500 signs from ASL-LEX, the world's largest interactive ASL database. Caselli says they began by using the AI algorithm to estimate the position of the signer's body and limbs.

"We feed the video into a machine learning algorithm that uses computer vision to figure out where key points on the body are," says Caselli. "We can then figure out where the hands are relative to the face in each sign." The researchers then match that with data from ASL-LEX -- which was created with help from the Hariri Institute's Software & Application Innovation Lab -- about how often the signs and handshapes are used. They found, for example, that many signs that use common handshapes, such as the sign for children -- which uses a flat, open hand -- are produced further from the face than signs that use rare handshapes, like the one for light (see videos).

This project is part of a new and growing body of work connecting computing and sign language at BU.

"The team behind these projects is dynamic, with signing researchers working in collaboration with computer vision scientists," says Lauren Berger, a Deaf scientist and postdoctoral fellow at BU who works on computational approaches to sign language research. "Our varying perspectives, anchored by the oversight of researchers who are sensitive to Deaf culture, helps prevent cultural and language exploitation just for the sake of pushing forward the cutting edge of technology and science."

Understanding how sign languages work can help improve Deaf education, says Caselli, who hopes the latest findings also bring attention to the diversity in human languages and the extraordinary capabilities of the human mind.

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Higher education and language skills may help ward off dementia

New research has found that people with mild cognitive impairment may not inevitably develop dementia and, in fact, having higher education and advanced language skills more than doubles their chances of returning to normal.

The study, led by researchers at the University of Waterloo, may reassure those with mild cognitive impairment as it contradicts a common assumption that the condition is simply an early stage of dementia. People with mild cognitive impairment show signs of cognitive decline, but not enough to prevent them from performing typical daily tasks. They have been considered at higher risk of progressing to the more severe cognitive decline seen in dementia.

"Possessing high cognitive reserve -- based on education, high academic grades, and written language skills -- may predict what happens years after someone receives a diagnosis of mild cognitive impairment," said Suzanne Tyas, a professor in the School of Public Health Sciences at Waterloo and lead author. "Even after considering age and genetics -- established risk factors for dementia -- we found that higher levels of education more than doubled the chances that people with mild cognitive impairment would return to normal cognition instead of progressing to dementia."

The study also found that language skills, whether reflected in high grades in English in school or in strong writing that was grammatically complex and full of ideas, were also protective.

The researchers discovered that almost one-third of 472 women diagnosed with mild cognitive impairment reverted to normal cognition at least once over an average of eight-and-a-half years following their diagnosis, with more than 80 per cent of them never developing dementia.

Almost another third of the total number progressed to dementia without ever reverting to normal cognition, while three per cent stayed in the mild cognitive impairment stage, and 36 per cent died. None of the participants reverted from dementia to mild cognitive impairment.

The researchers also highlighted that reverse transitions are much more common than progressing to dementia in relatively younger individuals who didn't carry a certain genetic risk factor and had high levels of education and language skills.

"We can't do much about age and genetics, so it's encouraging that our findings show that there are other ways to reduce the risk of dementia, such as building cognitive reserve through education and language skills earlier in life," Tyas said.

The study's findings have implications for treatment and research in people with mild cognitive impairment.

"If individuals with higher cognitive reserve are more likely to improve even without treatment, then this needs to be taken into consideration when recruiting participants for clinical trials of prospective treatments and when interpreting the results of these trials," Tyas said, adding there's no cure for most causes of dementia, so prevention is key.

For the analysis, researchers used complex modelling with data drawn from a longitudinal study called the Nun Study, which looked at older, highly educated religious sisters. The participants were mostly homogeneous, with similar socioeconomic status and marital and reproductive history, strengthening the conclusions of this work.

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Improving reading skills through action video games

Decoding letters into sound is a key point in learning to read but is not enough to master it. "Reading calls upon several other essential mechanisms that we don't necessarily think about, such as knowing how to move our eyes on the page or how to use our working memory to link words together in a coherent sentence," points out Daphné Bavelier, a professor in the Psychology Section of the Faculty of Psychology and Educational Sciences (FPSE) at the UNIGE. "These other skills, such as vision, the deployment of attention, working memory, and cognitive flexibility, are known to be improved by action video games," explains Angela Pasqualotto, first author of this study, which is based on her PhD thesis at the Department of Psychology and Cognitive Science of the University of Trento under the direction of Professors Venuti and De Angeli.

A child-friendly action video game to support learning

With this in mind, a video game was designed that combines action video games with mini games that train different executive functions, such as working memory, inhibition and cognitive flexibility, functions that are called upon during reading. "The universe of this game is an alternative world in which the child, accompanied by his Raku, a flying creature, must carry out different missions to save planets and progress in the game," Angela Pasqualotto adds. The idea is to reproduce the components of an action game, without incorporating violence, so that it is suitable for young children. "For example, the Raku flies through a meteor shower, moving around to avoid those or aiming at them to weaken their impact, while collecting useful resources for the rest of the game, a bit like what you find in action video games."

The scientists then worked with 150 Italian schoolchildren aged 8 to 12, divided into two groups: the first one played the video game developed by the team, and the second one played Scratch, a game that teaches children how to code. Both games require attentional control and executive functions, but in different manners. The action video game requires children to perform tasks within a time limit such as remembering a sequence of symbols or responding only when the Raku makes a specific sound while increasing the difficulty of these tasks according to the child's performance. Scratch, the control game, requires planning, reasoning and problem solving. Children must manipulate objects and logical structures to establish the desired programming sequence.

"First, we tested the children's ability to read words, non-words and paragraphs, and also we conducted an attention test that measures the child's attentional control, a capacity we know is trained by action video games," explains Daphne Bavelier. The children then followed the training with either the action video game or the control game, for six weeks, two hours a week under supervision at school. Children were tested at school by clinicians of the Laboratory of Observation Diagnosis and Education (UNITN).

Long-term improvement in reading skills

Shortly after the end of the training, the scientists repeated the tests on both groups of children. "We found a 7-fold improvement in attentional control in the children who played the action video game compared to the control group," says Angela Pasqualotto. Even more remarkably, the research team observed a clear enhancement in reading, not only in terms of reading speed, but also in accuracy, whereas no improvement was noted for the control group. This improvement in literacy occurs even though the action video game does not require any reading activity.

"What is particularly interesting about this study is that we carried out three further assessment tests at 6 months, 12 months and 18 months after training. On each occasion, the trained children performed better than the control group, which proves that these improvements were sustained," Angela Pasqualotto says. Moreover, the grades in Italian of the trained children became significantly better over time, showing a virtuous improvement in learning ability. "The effects are thus long-term, in line with the action video game strengthening the ability to learn how to learn," says Daphne Bavelier.

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Geneticists’ new research on ancient Britain contains insights on language, ancestry, kinship, milk

New research revealing a major migration to the island of Great Britain offers fresh insights into the languages spoken at the time, the ancestry of present-day England and Wales, and even ancient habits of dairy consumption.

The findings are described in Nature by a team of more than 200 international researchers led by Harvard geneticists David Reich and Nick Patterson. Michael Isakov, a Harvard undergraduate who discovered the existence of the 3,000-year-old migration, is one of the co-first authors.

The analysis is one of two Reich-led studies of DNA data from ancient Britain that Nature published on Tuesday. Both highlight technological advances in large-scale genomics and open new windows into the lives of ancient people.

"This shows the power of large-scale genetic data in concert with archaeological and other data to get rich information about our past from a time before writing," said Reich, a professor in the Department of Human Evolutionary Biology and a professor of genetics at Harvard Medical School. "The studies are not only important for Great Britain, where we now have far more ancient DNA data than in any other region, but also because of what they show about the promise of similar studies elsewhere in the world."

The researchers analyzed the DNA of 793 newly reported individuals in the largest genome-wide study involving ancient humans. Their findings reveal a large-scale migration likely from somewhere in France to the southern part of Great Britain, or modern-day England and Wales, that eventually replaced about 50 percent of the ancestry of the island during the Late Bronze Age (1200 to 800 B.C.).

The study supports a recent theory that early Celtic languages came to Great Britain from France during the Late Bronze Age. It challenges two prominent theories: that the languages arrived hundreds of years later, in the Iron Age, or 1,500 years earlier at the dawn of the Bronze Age.

Previous research has shown that large-scale movement often accompanied language changes in pre-state societies. The Reich team argues that this untold migration event makes more sense for the spread of early Celtic languages into Britain.

"By using genetic data to document times when there were large-scale movements of people into a region, we can identify plausible times for a language shift," Reich said. "Known Celtic languages are too similar in their vocabularies to plausibly descend from a common ancestor 4,500 years ago, which is the time of the earlier pulse of large-scale migration, and very little migration occurred in the Iron Age. If you're a serious scholar, the genetic data should make you adjust your beliefs: downweighting the scenario of early Celtic language coming in the Iron Age [and early Bronze Age] and upweighting the Late Bronze Age."

As part of the genetic analysis, the researchers found that the ability to digest cow's milk dramatically increased in Britain from 1200 to 200 B.C., which is about a millennium earlier than it did in central Europe. These findings illuminate a different role for dairy consumption in Britain during this period compared with the rest of mainland Europe. More study is needed to define that role, the researchers said. Increased milk tolerance would have provided a big advantage in the former of higher survival rates among the children of people carrying this genetic adaptation.

The newly discovered ancestry change happened around 3,000 years ago, more than a millennium and a half before the Saxon period. The team was aware of a migration into England at some point during this gap because of an observation they made in research published in 2016. That study showed that contemporary English people have more DNA from early European farmers than people who lived in England about 4,000 years ago. The team set out to collect DNA from later periods to detect the shift.

The discontinuity -- a specific point in time when the percentage of farmer ancestry in English genomes changed -- was first noticed in the summer of 2019 by Isakov, an applied mathematics concentrator. He had started working as a researcher in Reich's lab the summer after his first year and was able to increase the statistical power of the group's ancestry tests. When he noticed some outliers in the data from people living 3,000 years ago, he led a closer analysis and discovered the migration.

"It's an extraordinary outcome and I'm very happy that I was able to get through it," said Isakov, who will graduate in May.

The second paper looks at kinship practices of 35 individuals who lived about 5,700 years ago and were buried in a tomb at Hazleton North in Gloucestershire, England. The researchers found a 27-person family -- three times larger than the second-largest documented ancient family -- whose kin relationships could be precisely determined by analyzing their DNA. The team created a family tree that covered five generations and found examples of polygyny, polyandry, adoption, and a key role for both patrilineal and matrilineal descent.

The lab's research illustrates the interdisciplinary collaborations that are required to tell the richest stories of the ancient past, Isakov said.

"It's sort of incredible that we have geneticists, we have statisticians, we have archaeologists, linguists, and even chemical analysis coming together. I think that the fact that we're able to like merge all these fields and have an actual insight that's culturally important is a great example of interdisciplinary science."

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1,500 endangered languages at high risk of being lost this century

A world-first study warns 1,500 endangered languages could no longer be spoken by the end of this century.

The study, led by The Australian National University (ANU), identified predictors that put endangered languages at high risk.

Co-author Professor Lindell Bromham said that of the world's 7,000 recognised languages, around half were currently endangered.

"We found that without immediate intervention, language loss could triple in the next 40 years. And by the end of this century, 1,500 languages could cease to be spoken."

Published in Nature Ecology and Evolution, they study charts the widest range of factors ever putting endangered languages under pressure.

One finding was that more years of schooling increased the level of language endangerment. The researchers say it shows we need to build curricula that support bilingual education, fostering both indigenous language proficiency as well as use of regionally-dominant languages.

"Across the 51 factors or predictors we investigated, we also found some really unexpected and surprising pressure points. This included road density," Professor Bromham said.

"Contact with other local languages is not the problem -- in fact languages in contact with many other Indigenous languages tend to be less endangered.

"But we found that the more roads there are, connecting country to city, and villages to towns, the higher the risk of languages being endangered. It's as if roads are helping dominant languages 'steam roll' over other smaller languages."

The researchers say the findings also have important lessons for preserving many of the endangered languages spoken by Australia's First Nations peoples.

"Australia has the dubious distinction of having one of the highest rates of language loss worldwide," Professor Felicity Meakins, from the University of Queensland and one of the study's co-authors, said.

"Prior to colonisation, more than 250 First Nations languages were spoken, and multilingualism was the norm. Now, only 40 languages are still spoken and just 12 are being learnt by children.

"First Nations languages need funding and support. Australia only spends $20.89 annually per capita of the Indigenous population on languages, which is abysmal compared with Canada's $69.30 and New Zealand's $296.44."

Professor Bromham said that as the world enters the UNESCO Decade of Indigenous Languages in 2022, the study's findings were a vital reminder that more action was urgently needed to preserve at-risk languages.

"When a language is lost, or is 'Sleeping' as we say for languages that are no longer spoken, we lose so much of our human cultural diversity. Every language is brilliant in its own way.

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Using mechanical tools improves our language skills, study finds

Our ability to understand the syntax of complex sentences is one of the most difficult language skills to acquire. In 2019, research had revealed a correlation between being particularly proficient in tool use and having good syntactic ability. A new study, by researchers from Inserm, CNRS, Université Claude Bernard Lyon 1 and Université Lumière Lyon 2 in collaboration with Karolinska Institutet in Sweden, has now shown that both skills rely on the same neurological resources, which are located in the same brain region. Furthermore, motor training using a tool improves our ability to understand the syntax of complex sentences and -- vice-versa -- syntactic training improves our proficiency in using tools. These findings could be applied clinically to support the rehabilitation of patients having lost some of their language skills.

This study is published in November 2021 in the journal Science.

Language has long been considered a very complex skill, mobilizing specific brain networks. However, in recent years, scientists have revisited this idea.

Research suggests that brain areas, which control certain linguistic functions, such as the processing of word meanings, are also involved in controlling fine motor skills. However, brain imaging had not provided evidence of such links between language and the use of tools. Paleo-neurobiology has also shown that the brain regions associated with language had increased in our ancestors during periods of technological boom, when the use of tools became more widespread.

When considering this data, research teams couldn't help wondering: what if the use of certain tools, which involves complex movements, relies on the same brain resources as those mobilized in complex linguistic functions such as syntax?

Syntax exercises and use of tongs

In 2019, Inserm researcher Claudio Brozzoli in collaboration with CNRS researcher Alice C. Roy and their team had shown that individuals who are particularly proficient in the use of tools were also generally better at handling the finer points of Swedish syntax.

In order to explore the subject in greater depth, the same team, in collaboration with CNRS researcher Véronique Boulenger, developed a series of experiments that relied on brain imaging techniques (functional magnetic resonance imaging or MRI) and behavioral measurements. The participants were asked to complete several tests consisting of motor training using 30 cm-long pliers and syntax exercises in French. This enabled the scientists to identify the brain networks specific to each task, but also common to both tasks.

They discovered for the first time that the handling of the tool and the syntax exercises produced brain activations in common areas, with the same spatial distribution, in a region called the "basal ganglia."

Cognitive training

Given that these two skill types use the same brain resources, is it possible to train one in order to improve the other? Does motor training with the mechanical tongs improve the understanding of complex phrases? In the second part of their study, the scientists looked at these issues and showed that this is indeed the case.

This time, the participants were asked to perform a syntactic comprehension task before and after 30 minutes of motor training with the pliers (see box for details of the experiment). With this, the researchers demonstrated that motor training with the tool leads to improved performance in syntactic comprehension exercises.

In addition, the findings show that the reverse is also true: training of language faculties, with exercises to understand sentences with complex structure, improved motor performance with the tool.

The scientists are now thinking about how to best apply these findings in the clinical setting."We are currently devising protocols that could be put in place to support the rehabilitation and recovery of language skills of patients with relatively preserved motor faculties, such as young people with developmental language disorders. Beyond these innovative applications, these findings also give us an insight into how language has evolved throughout history. When our ancestors began to develop and use tools, this proficiency profoundly changed the brain and imposed cognitive demands that may have led to the emergence of certain functions such as syntax," concludes Brozzoli.

Motor training and syntax exercises

The motor training involved using the pliers to insert small pegs into holes that matched their shape but with differing orientations.

The syntax exercises which were completed before and after this training consisted of reading sentences with a simple syntax, such as "The scientist who admires the poet writes an article" or with a more complex syntax, such as "The scientist whom the poet admires writes an article." Then the participants had to decide whether statements such as "The poet admires the scientist" were true or false. Sentences with the French object relative pronoun "que" are more difficult to process and therefore performance was generally poorer.

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Bilingualism comes naturally to our brains

The brain uses a shared mechanism for combining words from a single language and for combining words from two different languages, a team of neuroscientists has discovered. Its findings indicate that language switching is natural for those who are bilingual because the brain has a mechanism that does not detect that the language has switched, allowing for a seamless transition in comprehending more than one language at once.

"Our brains are capable of engaging in multiple languages," explains Sarah Phillips, a New York University doctoral candidate and the lead author of the paper, which appears in the journal eNeuro. "Languages may differ in what sounds they use and how they organize words to form sentences. However, all languages involve the process of combining words to express complex thoughts."

"Bilinguals show a fascinating version of this process -- their brains readily combine words from different languages together, much like when combining words from the same language," adds Liina Pylkkänen, a professor in NYU's Department of Linguistics and Department of Psychology and the senior author of the paper.

An estimated 60 million in the U.S. use two or more languages, according to the U.S. Census. However, despite the widespread nature of bi- and multilingualism, domestically and globally, the neurological mechanisms used to understand and produce more than one language are not well understood.

This terrain is an intriguing one; bilinguals often mix their two languages together as they converse with one another, raising questions about how the brain functions in such exchanges.

To better understand these processes, Phillips and Pylkkänen, who is also part of the NYU Abu Dhabi Institute, explored whether bilinguals interpret these mixed-language expressions using the same mechanisms as when comprehending single-language expressions or, alternatively, if understanding mixed-language expressions engages the brain in a unique way.

To test this, the scientists measured the neural activity of Korean/English bilinguals.

Here, the study's subjects viewed a series of word combinations and pictures on a computer screen. They then had to indicate whether or not the picture matched the preceding words. The words either formed a two-word sentence or were simply a pair of verbs that did not combine with each other into a meaningful phrase (e.g., "icicles melt" vs. "jump melt"). In some instances, the two words came from a single language (English or Korean) while in others both languages were used, with the latter mimicking mixed-language conversations.

In order to measure the study subjects' brain activity during these experiments, the researchers deployed magnetoencephalography (MEG), a technique that maps neural activity by recording magnetic fields generated by the electrical currents produced by our brains.

The recordings showed that Korean/English bilinguals, in interpreting mixed-language expressions, used the same neural mechanism as they did while interpreting single-language expressions.

Specifically, the brain's left anterior temporal lobe, a brain region well-studied for its role in combining the meanings of multiple words, was insensitive to whether the words it received were from the same language or from different languages. This region, then, proceeded to combine words into more complex meanings so long as the meanings of the two words combined together into a more complex meaning.

These findings suggest that language switching is natural for bilinguals because the brain has a combinatory mechanism that does not "see" that the language has switched.

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Major branches in the tree of language reconstructed

The diversity of human languages can be likened to branches on a tree. If you're reading this in English, you're on a branch that traces back to a common ancestor with Scots, which traces back to a more distant ancestor that split off into German and Dutch. Moving further in, there's the European branch that gave rise to Germanic; Celtic; Albanian; the Slavic languages; the Romance languages like Italian and Spanish; Armenian; Baltic; and Hellenic Greek. Before this branch, and some 5,000 years into human history, there's Indo-European -- a major proto-language that split into the European branch on one side, and on the other, the Indo-Iranian ancestor of modern Persian, Nepali, Bengali, Hindi, and many more.

One of the defining goals of historical linguistics is to map the ancestry of modern languages as far back as it will go -- perhaps, some linguists hope, to a single common ancestor that would constitute the trunk of the metaphorical tree. But while many thrilling connections have been suggested based on systemic comparisons of data from most of the world's languages, much of the work, which goes back as early as the 1800s, has been prone to error. Linguists are still debating over the internal structure of such well-established families as Indo-European, and over the very existence of chronologically deeper and larger families.

To test which branches hold up under the weight of scrutiny, a team of researchers associated with the Evolution of Human Languages program is using a novel technique to comb through the data and to reconstruct major branches in the linguistic tree. In two recent papers, they examine the ~5,000-year-old Indo-European family, which has been well studied, and a more tenuous, older branch known as the Altaic macrofamily, which is thought to connect the linguistic ancestors of such distant languages as Turkish, Mongolian, Korean, and Japanese.

"The deeper you want to go back in time, the less you can rely on classic methods of language comparison to find meaningful correlates," says co-author George Starostin, an Santa Fe Institute external professor based at the Higher School of Economics in Moscow. He explains that one of the major challenges when comparing across languages is distinguishing between words that have similar sounds and meanings because they might descend from a common ancestor, from those that are similar because their cultures borrowed terms from each other in the more recent past.

"We have to get to the deepest layer of language to identify its ancestry because the outer layers, they are contaminated. They get easily corrupted by replacements and borrowings," he says.

To tap into the core layers of language, Starostin's team starts with an established list of core, universal concepts from the human experience. It includes meanings like "rock," "fire," "cloud," "two," "hand," and "human," amongst 110 total concepts. Working from this list, the researchers then use classic methods of linguistic reconstruction to come up with a number of word shapes which they then match with specific meanings from the list. The approach, dubbed "onomasiological reconstruction," notably differs from traditional approaches to comparative linguistics because it focuses on finding which words were used to express a given meaning in the proto-language, rather than on reconstructing phonetic shapes of those words and associating them with a vague cloud of meanings.

Their latest re-classification of the Indo-European family, which applies the onomasiological principle and was published in the journal Linguistics, confirmed well-documented genealogies in the literature. Similar research on the Eurasian Altaic language group, whose proto-language dates back an estimated 8,000 years, confirmed a positive signal of a relationship between most major branches of Altaic -- Turkic, Mongolic, Tungusic, and Japanese. However, it failed to reproduce a previously published relationship between Korean and the other languages in the Altaic grouping. This could either mean that the new criteria were too strict or (less likely) that previous groupings were incorrect.

As the researchers test and reconstruct the branches of human language, one of the ultimate goals is to understand the evolutionary paths languages follow over generations, much like evolutionary biologists do for living organisms.

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Struggling to learn a new language? Blame it on your stable brain

A study in patients with epilepsy is helping researchers understand how the brain manages the task of learning a new language while retaining our mother tongue. The study, by neuroscientists at UC San Francisco, sheds light on the age-old question of why it's so difficult to learn a second language as an adult.

The somewhat surprising results gave the team a window into how the brain navigates the tradeoff between neuroplasticity -- the ability to grow new connections between neurons when learning new things -- and stability, which allows us to maintain the integrated networks of things we've already learned. The findings appear in the Aug. 30, 2021, issue of Proceedings of the National Academy of Sciences.

"When learning a new language, our brains are somehow accommodating both of these forces as they're competing against each other," said Matt Leonard, PhD, assistant professor of neurological surgery and a member of the UCSF Weill Institute for Neurosciences.

By using electrodes on the surface of the brain to follow high-resolution neural signals, the team found that clusters of neurons scattered throughout the speech cortex appear to fine-tune themselves as a listener gains familiarity with foreign sounds.

"These are our first insights into what's changing in the brain between first hearing the sounds of a foreign language and being able to recognize them," said Leonard, who is a principal investigator on the study.

"That in-between stage is a crucial step in language learning but has been difficult to tackle, because the process is dynamic and unique to the individual," he said. "With this study, we were able to see what's actually happening in the brain regions involved in differentiating sounds during this initial phase of learning."

Brain Activity Shifts as Foreign Sounds Become Familiar

Learning the sounds of a new language is the first step in learning to use that language, said Leonard. So for this study, Leonard and lead author and postdoctoral scholar Han Yi, PhD, investigated how the activity in the dispersed brain regions associated with language shifted as the listener became more familiar with the foreign sounds.

The team worked with 10 patient volunteers, aged 19 to 59, whose native language is English, and asked them to recognize speech sounds in Mandarin. Mandarin is a tonal language in which the meaning of the word relies not only on the vowel and consonant sounds but also on subtle changes in the pitch of the voice, known as tones. Speakers of non-tonal languages like English often find it very challenging to discern these unfamiliar sounds.

Each of the volunteers had previously had brain surgery, during which electrodes were implanted in their brains to locate the source of their seizures. The study included seven patients at the UCSF Epilepsy Center, and three in the Epilepsy Center at the University of Iowa Hospitals and Clinics. The volunteers agreed to allow Leonard and his team to gather data from high-density, 256-channel electrodes placed on the surface of the brain regions that process speech sounds.

Over the course of the next few days, Leonard and Yi worked with the volunteers individually, playing recordings of several native Mandarin speakers of different ages, both male and female, pronouncing syllables like "ma" and "di" using each of the four tones. After each sound, the patient indicated whether they thought the tone was going up, down, up and then down, or staying flat, and received feedback on whether they were correct. Patients repeated this task about 200 times, over several 5- to 10-minute sessions.

After that brief amount of time, Leonard said, people had gotten through the initial learning phase and had become somewhat adept at categorizing the sounds.

"We also saw a lot of variability," he added. "Some people will get a bunch of trials right and then they'll start getting them wrong and then they'll get it right again in this kind of up-and-down that seems to be part of the learning process."

Learning New Sounds Involves Fine-Tuning Neural "Knobs"

When Leonard and Yi looked at the neural signals generated by the language learners, they saw a pattern that both surprised them and explained the performance curve they'd observed.

Data from other published studies suggested that activity across the speech cortex might increase as a person becomes more familiar with the language. What the researchers discovered instead was a spectrum of changes distributed throughout that speech cortex; with activity increasing in some areas but decreasing in others, maintaining a careful balance.

Those changes might be related to a brain area becoming tuned in to a particular tone, said Yi.

"We could see some groups of cells would respond more to the falling tone, and just keep ramping up their response, while right next to it another group of cells would increasingly engage when the person heard the dipping tone," Yi said. "It's as if these small clumps of neurons took on different roles."

In addition, which brain regions were more activated by which tone varied across individuals.

"It's more like each person's brain has a unique set of knobs that are getting fine-tuned while they're becoming familiar with these sounds," Leonard said.

Leonard and Yi think this may explain why some people pick up the sounds much more easily than others, as each unique brain strikes its own balance between maintaining the stability of the native language while calling on the plasticity required to learn a new one.

"The volunteers were able to learn the tones in Mandarin without affecting their ability to perceive pitch in English or in music," said Leonard. "These little neural knobs were all communicating with each other to reach the point where they can do the task correctly by working together."

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Exploring the past: Computational models shed new light on the evolution of prehistoric languages

A new linguistic study sheds light on the nature of languages spoken before the written period, using computational modeling to reconstruct the grammar of the 6500-7000 year-old Proto-Indo-European language, which is the ancestor of most languages of Eurasia, including English and Hindi. The model employed makes it possible to observe evolutionary trends in language over the millennia. The article, "Reconstructing the evolution of Indo-European grammar," authored by Gerd Carling (Lund University) and Chundra Cathcart (University of Zurich) will be published in the September 2021 issue of the scholarly journal Language.

In the article, Carling & Cathcart use a database of features from 125 different languages of the Indo-European family, including extinct languages such as Sanskrit and Latin. Features include most of the differences that make the languages difficult to learn, such as differentiation in word order (the girl throws the stone in English or caitheann an cailín an chloch "throws the girl the stone" in Irish), gender (the apple in English or der Apfel in German), number of cases, number of forms of the verb, or whether languages have prepositions or postpositions (to the house in English but ghar ko "house-to" in Hindi). With the aid of methods adopted from computational biology, the authors use known grammars to reconstruct grammars of unknown prehistorical periods.

The reconstruction of Indo-European grammar has been the subject of lengthy discussion for over a century. In the 19th century, scholars held the view that the ancient written languages, such as Classical Greek, were most similar to the reconstructed Proto-Indo-European language. The discovery of the archaic but highly dissimilar Hittite language in the early 20th century shifted the focus. Instead, scholars believed that Proto-Indo-European was a language with a structure more similar to non-Indo-European languages of Eurasia such as Basque or languages of the Caucasus region.

The study confirms that Proto-Indo-European was similar to Classical Greek and Sanskrit, supporting the theory of the 19th century scholars. However, the study also provides new insights into the mechanisms of language change. Some features of the proto-language were very stable and dominant over time. Moreover, features of higher prominence and frequency were less likely to change.

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