Findings that have transformed the science of language
Guided by the Centre’s mission to transform the science of language, CoEDL researchers pushed the boundaries of their fields to produce many discoveries across a diverse range of questions. The Centre’s emphasis on linguistic diversity, for example, meant that CoEDL researchers sought previously undiscovered ways that languages can be built and set these new models against what is known about other languages. In a similar effort to challenge accepted wisdom, CoEDL members — knowing that much of the world is multilingual — showed that the language sciences have been held back by being largely based on the simplifying assumption that monolingualism is the norm. And research considering the balance between speech, gesture and sign in the development of language systems, or the history of this development and the diversity of languages it has produced, has shed new light on the emergence of language as one of the unique elements of the human condition.
CoEDL’s success is seen not only in the breadth of these discoveries, but also in combining methods and findings — in new ways and across disciplines — to enhance the understanding of language and the social, cultural, cognitive and technological processes it impacts. The selection of discoveries below shares some of this work.
CoEDL PhD student Tina Gregor uncovered the intriguing phenomenon of gender suppletion in the language Yelmek . Suppletion occurs when words are not formed in the predictable way. For example, when conjugating verbs in the past tense in English, we normally add -ed to verbs — count becomes counted — but this is not the case when go becomes went. Since forming new sentences depends on using regular rules, there are usually few suppletive sets per language. Tina discovered that Yelmek suppletes for the gender of objects, something no other language is known to do. The Yelmek words poyopoa (‘he held her’) and peŋepea (‘he held him’) show this divergence, with the stems oyopo and eŋepe differing depending on the gender of the object being held. Yelmek has dozens of pairs like this.
Following CoEDL Research Fellow Don Daniels’ fieldwork on the Trans New Guinea language Soq, Daniels and PI Greville Corbett established a new phenomenon termed repartitioning . Verbs in Soq have a four-way tense system, which divides time reference into the far past, the yesterday past, the ‘today until now’ present or the future. An exception to this system is the unique verb s- (‘stay’). It uses the same forms but divides time differently: the ‘yesterday past’ form means ‘yesterday until now’ and the ‘today until now’ form means ‘now’. Right meaning and wrong form — as with irregular verbs like go becoming went — is a familiar divergence but the irregularity of repartitioning — right form, wrong meaning — has not been observed before.
Engagement, in linguistics, is the use of inflections on verbs to indicate whether the speaker thinks their conversation partner is paying attention to an action they are talking about. French linguist Jon Landaburu first reported this phenomenon in the Colombian language Andoke. A major survey of engagement by Director Nick Evans and SCOPIC team members Henrik Bergqvist and Lila San Roque gathered evidence from many languages to set up a logical framework for exploring the phenomenon . Since then, scientific interest in engagement has escalated. A special journal issue of Open Linguistics on ‘Explorations in Engagement’ was published in 2019, including an important article by CoEDL Research Fellow Bruno Olsson exploring new techniques for understanding engagement based on video-recorded interaction .
Australian languages are famous for their free word order and offer a special challenge to understanding how speakers plan their sentences. Research by CI Evan Kidd, CI Rachel Nordlinger and Research Fellow Gabriela Garrido Rodriguez — which began in CoEDL before receiving ARC Discovery funding — used mobile eye-trackers to investigate this among speakers of the Australian language Murrinhpatha. Their findings — published in the field’s premier journal, Language — indicated that Murrinhpatha speakers begin planning their sentences much earlier than English speakers, probably because they need a holistic overview of the situation before uttering their first word
Various studies from CoEDL members have investigated how children learn complex language structures; for instance, Research Fellow William Forshaw’s research on polysynthetic verbs in Murrinhpatha [6, 7], or Research Fellow Hannah Sarvasy’s work on the paragraph-long sentences termed clause chains in the Papuan language Nungon . Further research by Affiliate Barbara Kelly and collaborators  and by CI Evan Kidd and Rowena Garcia  shows that children learning these languages appear to master complex structures on par with, or even ahead of, English-learning children mastering equivalent structures. This work pushes the field of developmental psycholinguistics to a wider range of languages and suggests that complexity or rarity may not simply signify difficulty with acquisition.
Any theory of language dynamics must account for the individual variation between language as a shared social system and language as an individual skill or activity. CoEDL members investigated this question in different ways. CI Evan Kidd, Research Fellow Seamus Donnelly and PI Morten Christiansen assessed individual differences in learning and processing ; Evan Kidd and Joanne Arciuli also showed statistically that children’s very early abilities to learn individual words strongly predicted their later acquisition of syntax . Research Fellow Danielle Barth and other SCOPIC project colleagues used ‘parallax corpora’ to investigate the relative contribution of a speaker’s language to how they frame utterances against a background of individual variation .
Multilingualism proved a fruitful area for CoEDL research. CI Alan Rumsey surveyed the traditional multilingual nature of Indigenous Australian societies , while Research Fellows Ruth Singer and Jill Vaughan reviewed the varied forms multilingualism takes worldwide in a special issue of Language & Communication on Indigenous Multilingualisms . PhD student Catalina Torres’s thesis examined intonation and bilingual speech processes in Lifou, New Caledonia . The highly-cited study by Jan-Willem van Leussen and CI Paola Escudero presents a revised model for understanding how second languages are acquired in relationship to a speaker’s first language . In the context of language contact and change, CI Felicity Meakins, CI Caroline Jones and Cassandra Algy showed the impacts of a community shifting from one language to another on the way bilingual speakers in that community thought about space .
Research by CI Catherine Travis and PI Rena Torres Cacoullos overturned a widespread dogma that, over time, the two languages spoken in bilingual communities grow more similar as speakers streamline their production mechanisms into a single cognitive workflow. Bilingualism in the Community: Code-switching and Grammars in Contact puts forward a study of English-Spanish bilinguals in New Mexico, the United States, whose community has been bilingual for centuries . This research showed that the expected convergence has not yet occurred, suggesting speakers are able to maintain distinct systems over many generations.
CI Anne Cutler (†), PhD student Jiyoun Choi and Mirjam Broersma made an important contribution to understanding how the languages we learn restructure our minds and how long this effect lasts [20, 21]. They looked at people who had been adopted from Korea to the Netherlands in the first few months of life. Although these people had not learned Korean even in childhood, the study showed that, as adults, they could still produce certain Korean sounds they had been exposed to in infancy. This suggests that bilingual knowledge acquired even at six months persists, sometimes subconsciously, into adulthood.
In a study comparing Dutch-English bilinguals and English monolinguals, Research Fellow Mark Ellison and Affiliate Luisa Miceli discovered an unconscious process they label Doppel avoidance . Doppel avoidance helps bilingual speakers keep their languages apart by avoiding words that sound the same across the two languages. For example, Dutch-English bilinguals are more likely than English monolinguals to select picture over photo, since photo has a Dutch ‘doppel’ (fotograaf) but picture does not. They hypothesise that this mechanism makes it easier to monitor which language is being spoken.
Research by Director Nick Evans proposed a resolution to the debate between monogenetic (single emergence) and polygenetic (multiple emergences) perspectives on the origins of human language . He proposed ‘primal multilingualism’ between half-developed languages, each with complementary innovations, lay at the heart of how language evolved. The plausibility of this theoretical model was amplified in work by CI Felicity Meakins and her collaborators, who used techniques from population biology to explore how new languages can arise by merging elements drawn from two ‘parent languages’ into elaborate systems . This finding contradicts the long-held belief that the simplest elements from contributing languages are selected for as a new language emerges.
Foundational work by Research Fellow Ron Planer and CI Kim Sterelny put forward a new, gradualist account of the emergence of language as the product of over a million years of developing communications technologies and cognitive capacities. Their work culminated in the book From Sign to Symbol, which considers the insights that archaeological and biological evidence can give into linguistic history; the relationship between cognitive evolution and language use; comparisons between the communication practices of humans and our closest great-ape relatives; social and economic influences on language development; the shift between gestural to vocal modes of communication, and more . This work also brought the interdisciplinary evolutionary problems of linguistic diversity to the attention of biologists and philosophers through special journal issues of Biology & Philosophy  and Biological Theory .
PI Morten Christiansen and Nick Chater showed how theories of language evolution can integrate material from observable experimental effects in their influential book Creating Language . This research reveals how the iterated effects of processing and learning constraints can nudge, over hundreds of generations, the evolution of language onto particular paths, without invoking any hardwired ‘universal grammar’. The conceptual framework for integrating evolutionary theory with the systematic study of linguistic diversity is set out by Director Nick Evans, who shows how culture, demography and other factors can push linguistic evolution in different directions .
 Gregor, Tina. 2021. A documentation and description of Yelmek. PhD Thesis, Australian National University.
 Don Daniels, and Greville Corbett. 2019. "Repartitioning." Language. 95 (4): 711-750. doi: 10.1353/lan.2019.0071.
 Evans, Nicholas, Henrik Bergqvist and Lila San Roque. 2018. The grammar of engagement: Part I, Fundamentals. Language and Cognition. 10:110-40. DOI: 10.1017/langcog.2017.21.
 Bruno Olsson. 2019. "The Absconditive revealed: Attention alignment in the grammar of Coastal Marind." Open Linguistics. 5 (1): 136-155. doi: 10.1515/opli-2019-0009.
 Rachel Nordlinger, Gabriela Garrido Rodriguez, and Evan Kidd. 2022. Sentence planning and production in Murrinhpatha, an Australian 'free word order' language. Language. 98 (2): 187-220. doi: 10.1353/lan.2022.0008.
 Forshaw, William. 2021. The Acquisition of Complex Morphology: Insights from Murrinhpatha. John Benjamins. https://doi.org/10.1075/tilar.30.
 Forshaw, William, Davidson, Lucinda, Kelly, Barbara, Nordlinger, Rachel, Wigglesworth, Gillian, and Blythe, Joe. 2017. The Acquisition of Murrinhpatha (Northern Australia). In The Oxford Handbook of Polysynthesis. Oxford University Press. pp. 473–94. https://minerva-access.unimelb.edu.au/bitstream/handle/
 Kelly, Barbara, Forshaw, William, Nordlinger, Rachel, and Wigglesworth, Gillian. 2015. Linguistic Diversity in First Language Acquisition Research: Moving beyond the Challenges. First Language. 35 (4–5): 286–304. https://doi.org/10.1177/0142723715602350.
 Kidd, Evan and Rowena Garcia. 2022. How Diverse Is Child Language Acquisition Research? First Language. https://doi.org/https://doi.org/10.1177/01427237211066405 https://doi.org/https://doi.org/10.1177/01427237211066405.
 Kidd, Evan, Donnelly, Seamus, and Morten Christiansen. 2018. Individual Differences in Language Acquisition and Processing. Trends in Cognitive Science. 22(2): 152–169. https://doi.org/10.1016/j.tics.2017.11.006
 Evan Kidd, and Joanne Arciuli. 2015. "Individual differences in statistical learning predict chlidren's comprehension of syntax." Child Development. 87 (1): 184-193. doi: 10.1111/cdev.12461.
 Barth, Danielle, Evans, Nicholas, Arka, I Wayan, Bergqvist, Henrik, Forker, Diana, Gipper, Sonja, Hodge, Gabrielle, Kashima, Eri, Kasuga, Yuki, Kawakami, Carine, Kimoto, Yukinori, Knuchel, Dominique, Kogura, Norikazu, Kurabe, Keita, Mansfield, John, Narrog, Heiko, Pratiwi, Desak Putu Eka, van Putten, Saskia, Senge, Chikako, Tykhostup, Olena, Haig, Geoffrey, Schnell, Stefan, and Seifart, Frank. 2021. "Language vs individuals in cross-linguistic corpus typology". In Doing Corpus-Based Typology With Spoken Language Corpora, 179-232. Honolulu, HI: University of Hawai'i Press.
 Rumsey, Alan. 2018. The Sociocultural Dynamics of Indigenous Multilingualism in Northwestern Australia. Language & Communication (Special Issue on Indigenous Multilingualisms). 62(Part B): 91–101. https://doi.org/10.1016/j.langcom.2018.04.011
 Vaughan, Jill, and Ruth Singer. 2018. Indigenous Multilingualisms Past and Present. Indigenous Multilingualisms (Language & Communication). 62 (Part B): 83–90,https://doi.org/10.1016/j.langcom.2018.06.003.
 van Leussen, Jan-Willem, and Paola Escudero. 2015. Learning to perceive and recognize a second language: the L2LP model revised. Frontiers in Psychology. 6. https://doi.org/10.3389/fpsyg.2015.01000
 Meakins, Felicity, Jones, Caroline, and Cassandra Algy. 2015. Bilingualism, language shift and the corresponding expansion of spatial cognitive systems. Language Sciences. 54: 1–13. https://doi.org/10.1016/j.langsci.2015.06.002
 Rena Torres Cacoullos, and Catherine Travis. 2018. Bilingualism in the Community: Code-switching and Grammars in Contact. Cambridge: Cambridge University Press. doi:10.1017/9781108235259
 Choi, Jiyoun, Broersma, Mirjam, and Anne Cutler. 2017. Early phonology revealed by international adoptees’ birth language retention. Proceedings of the National Academy of Sciences of the United States of America. 114(28): 7307–7312. https://doi.org/10.1073/pnas.1706405114
 Choi, Jiyoun, Cutler, Anne, and Mirjam Broersma. 2017. Early development of abstract language knowledge: Evidence from perception-production transfer of birth-language memory. Royal Society Open Science. 4(1): 160660. https://doi.org/10.1098/rsos.160660
 Ellison, Mark and Luisa Miceli. 2017. Language monitoring in bilinguals as a mechanism for rapid lexical divergence. Language. 93(2): 255–287.
 Evans, Nicholas. 2018. Did language evolve in multilingual settings? Biology and Philosophy 32.10.1007/s10539-018-9609-3.
 Felicity Meakins, Xia Hua, Cassandra Algy, and Lindell Bromham. 2019. "Birth of a new language does not favour simplification." Language. 95 (2): 294-332. doi: 10.1353/lan.2019.0032.
 Planer, Ronald, and Kim Sterelny. 2021. From signal to symbol. MIT Press. https://mitpress.mit.edu/9780262045971/from-signal-to-symbol/
 Special journal issue on “The Evolution of Language” in Biology & Philosophy. Volume 32, issue 6, December 2017. Issue editors: Kim Sterelny and Simon Greenhill. https://link.springer.com/journal/10539/volumes-and-issues/32-6
 Thematic journal issue on “Evolution of Kinship Systems” in Biological Theory. Volume 16, issue 3, September 2021. Issue editors: Nicholas Evans, Stephen Levinson and Kim Sterelny. https://link.springer.com/journal/13752/volumes-and-issues/16-3
 Christiansen, Morten, and Nick Chater. 2016. Creating language: Integrating evolution, acquisition, and processing. MIT Press. https://mitpress.mit.edu/books/creating-language
 Nicholas Evans. 2016. "Typology and coevolutionary linguistics." Linguistic Typology. 20 (3): 505-520. doi: http://doi.org/10.1515/lingty-2016-0023.