NEWCACTLJ UNIVER6ITt LICIRARY 20L 06107 0 iV-e- L---i°4- THE DEVELOPING BILINGUAL LEXICON Annabelle David Speech and Language Sciences Section School of Education, Communication and Language Sciences University of Newcastle upon Tyne Thesis submitted in fulfilment of the requirements for the degree of Doctor of Philosophy at the University of Newcastle upon Tyne. July, 2004 DECLARATION OF ORIGINALITY The material presented in this thesis is the original work of the candidate except as otherwise acknowledged. It has not been submitted previously, in part or whole, for any award, at any university, at any other time. Annabelle David 11 ACKNOWLEDGMENTS Financial support was provided by a Research Studentship from the ESRC (R422001241 15), as well as studentships from the University of Newcastle's Faculty of Humanities and Social Sciences and Alumni Fund; I would like to sincerely thank the many people who have been involved, directly or indirectly, in the various stages of the research reported in this thesis and have contributed to making the past few years a great learning experience: Barbara Pearson for her long distance support and help with some parts of the data analysis; Sophie Kern for allowing me to use the French adaptation of the CDI and part of her forming data; Barbara Dodd, Thomas flee, Zhu Hua and Ghada Khattab for their willingness to listen, comment, criticise and/or encourage; Sharon, Will, Jenni, Nicole, Juliane, John and all the others in the Speech section for their help and support; Graeme for checking my English; Li Wei for his all round support, advice and help with every stage of the doctoral process. In addition to being a great source of inspiration, be has taught me a Jot and given me numerous opportunities to try my hands at other aspects of academic life; Thomas, Floriane, Antonia, Emma, Duncan, Pénélope, Elisa, Jack, Oliver R, Liam, Rebecca, Oliver B and, last but by no means least, Anna and their parents and family for being so patient and cooperative over such a long period of time. Needless to say that without the children and their family, this thesis would not have been possible; My parents and brother for their constant interest, encouragement, love and unfailing confidence in all I do; Paulo, for his "consultancy services", chocolate supply, patience, love and unfading support. Sure, I could have written this thesis without him (actually, I did write this thesis without him! Not a word in here about micro- simulation!), but life without him would not be as exciting. 111 ABSTRACT It is often said that bilinguals are not two monolmguals in one person. But what does this really mean, especially in the context of bilingual acquisition? Despite the upsurge of case studies of bilingual children since the 1990's, the main central issue within the literature has largely remained focused on the one-vs. -two-system debate. Earlier studies focused on the question of whether bilingual children had a single/fused system or two separate/differentiated ones. There are a growing number of more recent studies focusing, instead, on the relationship between the two languages in the developing language system of the child. The study on which this thesis is based is the first longitudinal group study of lexical development of French-English bilingual children. The study aims to investigate the nature of the developing bilingual lexicon and its impact on the development of syntax. The key questions addressed in this new body of research include: are bilingual children developing in the same way and at the same rate as their monolingual peers; are there cross-linguistic influences on bilingual acquisition; are there features, patterns or processes specific to bilingual acquisition? We report findings from a longitudinal group study of 13 children between 1;4 and 3;0 who are acquiring French and English simultaneously within the one person - one language framework. The originality of this study lies in several main points. First of all, a larger number of children have been studied systematically than in traditional longitudinal studies, which are usually based on either cross-sectional sample or on single cases. Secondly, the children in this study have been systematically selected according to a set of sociolinguistic variables. This allows meaningful comparisons of the results as well as possible future replications of the study with even larger samples or with other language pairs. Furthermore, the methods used in the study are innovative in that both quantitative and qualitative methods have been used longitudinally as opposed to onLy longitudinal qualitative data or only quantitative cross-sectional data. The profiling of the bilingual lexicon reports that bilingual children's lexical categories in each language develop in a parallel manner whether or not the children are dominant in a language. The results also show that their development is very similar to previously reported data for monolingual children. Despite current theories, iv the evidence suggests that bilingual children produce translation equivalents before the 50-word stage. However, I attempt to bring forward the idea that cross-linguistic equivalents are different from synonyms within a language and so bilinguals cannot be compared to monolinguals in that respect. This thesis also sets the age of first word combinations for bilingual children to around 1 ;8 while claiming that this is only achieved after each language has reached the 50-word milestone. Finally, great variability is noted throughout the thesis in terms of lexical development amongst the children. Some of the differences are explained by socio-linguistic factors such as parental strategies and language exposure. Therefore, the importance of accounting for such factors when studying bilingual language development is underlined. Our understanding of bilingual acquisition centrally contributes to our understanding of language acquisition in general. Similar features of bilingual and monolingual acquisition have been highlighted throughout this thesis. Thus, the bilingual lexicon has shown to develop at a similar rate and in a similar manner as the monolingual one despite being strongly influenced by individual socio-linguistic factors. V PuBLIcATIoNs ARISING FROM THIS THEsIs Forthcoming publications: 1. David, A. & Li Wei (2004). The bilingual lexicon. In Cohen, J., McAlister, K., Rolstad, K., & MacSwan, 3. (Eds.). 1SB4: Proceedings of the 4th international Symposium on Bilingualism. Somerville, MA: Cascadilla Press. 2. David, A. & Li W. (2004). To what extent is code-switching dependent on a bilingual child's lexicon? Sociolinguistica, 18. Parts of this thesis have been presented at conferences: 1. The bilingual lexicon, 4th International Symposium on Bilingualism, Arizona State University, USA (April 2003). 2. The Principle of Contrast: a strategy or a constraint? Evidence from bilingual children, Child Language Seminar, University of Newcastle, UK (July 2003). 3. Who can we trust? - On using parental reports with bilingual children, Vocabulary knowledge and use: measurements and applications workshop, University of the West of England, Bristol, UK (January 2004). 4. Bilingual acquisition: theoretical implications of a longitudinal group study. Bilingualism in the 21st century, Welsh Institute for Social and Cultural Affairs at Bangor University (guest lecture), Wales (February 2004). 5. The impact of the lexicon on code-switching, 2nd Lisbon Meeting on Language Acquisition with Special Reference to Romance Languages, Universidade de Lisboa, Portugal (June 2004). VI 6. Can bilingual children produce two-word utterances with 50 words? 7th PG Conference in Theoretical and Applied Linguistics, University of Durham, UK (June 2004). 7. The role of parental strategies in a bilingual child's language development, Child Language Seminar, University of the West of England, Bristol, UK (July 2004). vi' TABLE OF CONTENTS ACKNOWLEDGMENTS ........................................................................... iii ABSTRACT .......................................................................................iv PUBLICATIONS& CONFERENCES ...............................................................vi TABLEOF CONTENTS ..........................................................................viii LISTOF FIGUREs ................................................................................xiii LISTOF TABLES ..................................................................................xv ABBREVIATIONS ...............................................................................xvii SECTIONI: PRESENTATION OF THE STUDY ........................................................... 1 CHAPTER 1: INTRODUCTION AND LITERATURE REVIEW................................ 2 1.1. INTRODUCTION .......................................................................................... 3 1.2. DEFINiTIONS OF CHILDHOOD BILINGUALISM ........................................... 5 1.3. OVERVIEW OF BILINGUAL LANGUAGE ACQUISITION RESEARCH.............7 1.4. THE ONE-VERSUS-TWO-SYSTEMS DEBATE ................................................ 9 1.4.1. The one-/unitary-system hypothesis................................................10 1.4.2. Issues with the unitary system hypothesis.......................................11 1.4.3. The two-/separate-systems hypothesis ............................................14 1.4.4. Other possibilities............................................................................16