Staff Profile of Professor Margaret Deuchar

Image of Professor Margaret Deuchar
Professor Margaret Deuchar
Emeritus Professor of Linguistics


Margaret Deuchar is Emeritus Professor in Linguistics at Bangor University and Affiliated Lecturer at the Dept of Theoretical and Applied Linguistics, University of Cambridge.  She is also affiliated with Cambridge Language Sciences and is a member of their Steering Committee. She has previously held posts at Lancaster, Sussex and Cambridge Universities. She graduated from Cambridge in Modern Languages (French and German) and obtained her PhD from Stanford University. Her thesis was on British Sign Language and was followed by a 1984 book, British Sign Language, published by Routledge. Shortly afterwards  she began research on bilingual acquisition and  published (with S. Quay) a book entitled Bilingual Acquisition: Theoretical Implications of a Case Study in 2000 with Oxford University Press.  She then extended her interests to bilingual adults, initially in the context of Wales, and was founding Director of the ESRC Centre for Research on Bilingualism in Theory and Practice (2007-2012). With the corpus-based group at the Centre she collected three corpora of code-switching data (Welsh-English, Welsh-Spanish and Spanish-English) which are available at She is currently working on a book to be published by John Benjamins and co-authored with Peredur Davies and Kevin Donnelly: Building and Using the Siarad Corpus: Bilingual conversations in Welsh and English.

Research Interests:

My current research interests are in code-switching. With a research team at Bangor we collected bilingual conversations from three groups of bilinguals: Welsh-English, Spanish-English and Welsh-Spanish. Data from the corpora have been used by my collaborators and myself to evaluate competing linguistic theories of code-switching (e.g. Herring et al 2010), to compare code-switching patterns in three bilingual communities (Carter et al 2011), challenge influential views of the boundary between code-switching and borrowing (Stammers & Deuchar 2012) and to establish the key extralinguistic factors influencing the production of code-switching (Deuchar et al forthcoming).

Media Interest 

  • Recorded interview about Welsh-English code-switching research project on Radio Wales programme Cutting Edge, transmitted on 16/07/06.   Listen here
  • Interview with in Welsh for Radio Cymru on 2/2/07 about new ESRC Centre for Research on Bilingualism.  Listen here
  • Interview in Welsh for television evening news on S4C about new ESRC Centre for Research on Bilingualism, transmitted on 2/02/07. Watch here
  • Article in Western Mail  “A linguistic weakness?  No, Welsh speakers’ brains are working in two languages at once” on 5/02/07 following interview by Rhodri Clark.
  • Article in Western Mail “Children bilingual in Welsh are half way to a third language” on 13/03/07 following interview by Rhodri Clark.
  • Interview on radio in Welsh on Radio Cymru (listen here) and in English on Radio Wales (listen here) on 16/11/07 about launch of new ESRC Centre for Research on Bilingualism.
  • Article in Western Mail “How a few English words can help to keep our Welsh language alive” on 24/11/07 following interview by Abbie Wightwick. Click here for the article

Key publications

  • Deuchar, M. (forthcoming) Introduction: Cross-language effects in bilingual production and comprehension: some novel findings. Bilingualism, Language and Cognition, doi:10.1071/S136672891600050X.
  • Deuchar, M. & Biberauer, T. (forthcoming). Doubling: an error or an illusion? Bilingualism, Language and Cognition doi:10.1017/S1366728916000043.
  • Deuchar, M., Donnelly, K. & Piercy, C. (forthcoming) “Mae pobl monolingual yn minority”: Factors favouring the production of code-switching by Welsh-English bilingual speakers. In Durham, M. and Morris, J. (eds) Sociolinguistics in Wales. Basingstoke: Palgrave MacMillan.
  • Deuchar, M. & Stammers, J.R. (2016) English-origin verbs in Welsh: Adjudicating between two theoretical approaches. Languages 2016, 1 (1), doi 10.3390/languages1010007.
  • Deuchar, M., Davies, P. Herring, J.R., Parafita Couto, M. & Carter, D. (2014) Building bilingual corpora: Welsh-English, Spanish-English and Spanish-Welsh. In E. M.Thomas and I. Mennen (eds) Advances in the Study of Bilingualism. Bristol: Multilingual Matters, 93-110.
  • Stammers, J. and Deuchar, M. (2012) Testing the nonce borrowing hypothesis: counter-evidence from English-origin verbs in Welsh. Bilingualism: Language and Cognition 15:3, 630-643.
  • Cater, D., Deuchar, M., Davies, P., Parafita Couto, M. (2011). A systematic comparison of factors affecting the choice of matrix language in three bilingual communities. Journal of Language Contact 4: 1-31.
  • Herring, J., Deuchar, M. Parafita Couto, M.C. & Moro Quintanilla, M. (2010), ‘‘When I went to Canada, I saw the madre’: evaluating two theories’ predictions about codeswitching between determiners and nouns using Spanish-English and Welsh-English bilingual corpora’, International Journal of Bilingual Education and Bilingualism 13:5, 553-573.