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Cambridge Language Sciences

Interdisciplinary Research Centre


My research interests are in bilingualism, particularly code-switching and I recently organised an interdisciplinary workshop on code-switching, held in Cambridge on 3-4th October 2016.  This led to the establishment of a code-switching reading group which met regularly in the year 2016-2017 and will continue in 2017-2018.  I have recently completed a book about Welsh-English code-switching to be published by John Benjamins. With a research team at Bangor University we collected bilingual conversations from three groups of bilinguals: Welsh-English, Spanish-English and Welsh-Spanish.  The conversations were transcribed and are made available in the public domain (  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).  Current work focuses on the choice of the matrix language in Spanish-English code-switching and how this is related to the structure of mixed nominal constructions.


Key publications: 

Deuchar, M., Davies, P. & Donnelly, K. (2018).  Building and Using the Siarad Corpus: Bilingual Conversations in Welsh and English.  Amsterdam: John Benjamins.

Wilson, C. & Deuchar, M. (2017)  Extralinguistic factors influencing the pronunciation of English by Welsh-English bilinguals. In Lauchlan, F. & Parafita Couto, M. (eds) Bilingualism and Minority Languages in Europe.  Newcastle upon Tyne: Cambridge Scholars Publishing, pp. 48-69.

Parafita Couto, M., Boutonnet, B., Hoshino, N., Davies, P., Deuchar, M. & Thierry, G. (2017).  Testing alternative theoretical accounts of code-switching using event-related potentials: a pilot study on Welsh-English.  In Lauchlan, F. & Parafita Couto, M. (eds) Bilingualism and Minority Languages in Europe.  Newcastle upon Tyne: Cambridge Scholars Publishing, pp. 240-254.

Deuchar, M. (2016)  Introduction: Cross-language effects in bilingual production and comprehension: some novel findings.  Bilingualism, Language and Cognition, 19(4), F1-F2. doi:10.1071/S136672891600050X.

Deuchar, M. & Biberauer, T. (2016).  Doubling: an error or an illusion?   Bilingualism, Language and Cognition 19(5), 881-882. doi:10.1017/S1366728916000043.


Deuchar, M., Donnelly, K. & Piercy, C. (2016) “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, pp. 209-240.

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.

Carter, 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.

Emeritus Professor of Linguistics, Bangor University
Affiliated Lecturer, Dept of Theoretical and Applied Linguistics
Professor Margaret  Deuchar