Author Biography vii Introduction 1 Part I Bilingual Adults and Children 5 1 Who Is Bilingual? 7 Definitions and Their Evolution 8 Describing Bilinguals 11 2 How Many Bilinguals Are There? 18 The Extent of Bilingualism 18 On the Difficulties of Counting People Who Are Bilingual 20 The Proportion of Bilinguals in a Number of Countries 23 Estimating the Percentage of Bilinguals in the World 27 3 Bilingual Infants' Journey to Language Separation 30 Perception Studies 31 Taking Pragmatics into Account 38 A Brief Account of Language Separation 40 Part II Linguistics and Neurolinguistics 43 4 Having an Accent in One of Your Languages 45 General Aspects 45 The Phonetic Characteristics of Accents 46 How Well Is Accented Speech Understood? 48 Factors that Affect the Degree of a Foreign Accent 50 Accent in a Third Language 55 5 Language Loss in Adults and Children 59 Language Loss in Adults 59 Language Loss in Young Children 63 6 Brain Injury and Bilingualism 72 A Personal Testimony 73 Language Impairment and Recovery in Bilingual Aphasia 74 Factors that Account for Impairment and Recovery 78 A Recent Meta-Analysis 81 Language Mixing and Aphasia 82 Part III Language Use and Language Processing 87 7 The Bilingual's Languages in Interaction 89 Choosing the Language of the Interaction 89 What Role for the Other Language? 92 Experimental Work on Language Mixing 94 The Language Mode Concept 97 8 What a Bilingual's Languages Are Used For 102 What Past Research Has Revealed 103 Recent Interest in Bilingual Language Use 104 Measuring Bilingual Language Use 106 Impact of Bilingual Language Use 109 9 Is Language Processing in Bilinguals Selective or Non-selective? 117 Language Perception and Comprehension 118 Spoken Language Production 122 Part IV Biculturalism and Personality 129 10 Bilinguals Who Are also Bicultural 131 Describing Biculturals 131 Becoming Bicultural and the Evolution of Biculturalism over Time 134 Acting Biculturally 137 Bicultural Identity 141 11 Change of Language, Change of Personality? 146 Opinions and Beliefs 147 Pioneering Research on the Question 147 Feeling Different When Using Different Languages 150 Is a Change of Personality Involved When Changing Languages? 152 An Explanation 154 Index 159

"From the mechanics of language processing to the lived realities of identity and cultural affiliation, Grosjean redefines bilingualism as a practice, intricately shaped by language use and loss."—Alene Moyer, Professor Emerita, University of Maryland "François Grosjean artfully presents a complex set of key questions pertaining to the study of bilingualism in a highly readable and engaging manner. The book is rich in information, including a lively presentation of the topics central to each chapter, and helpful details of selected studies to illustrate the state-of-the-art research on each theme addressed. His personal yet scientific style makes this probing book accessible to readers at all levels."—Mira Goral, Lehman College and the Graduate Center, The City University of New York "This book provides comprehensive answers to difficult issues regarding bilingualism. It discusses a wide range of topics ranging from language use and language processing for bilinguals, to biculturalism and change of personality. Readers will hear the voice of Professor Grosjean about his personal journey as a bilingual. Anyone who is interested in bilingualism should read the book. A landmark contribution to the field."—Ying-yi Hong, Choh-Ming Li Professor of Management, The Chinese University of Hong Kong The majority of people living around the world today are able to speak more than one language, yet many aspects of the nature and experience of bilingualism raise unresolved questions for researchers. Who exactly is bilingual? What is the extent of bilingualism? How do infant bilinguals who acquire two languages at the same time manage to separate them? Does language processing work differently when bilinguals are interacting with monolinguals and with bilinguals? When a speaker changes their language, do they also change aspects of their personality? In The Mysteries of Bilingualism: Unresolved Issues, eminent scholar François Grosjean provides a thorough examination of individual bilingualism that delves into unanswered questions and challenges many of the myths and misconceptions surrounding bilingualism. Through insightful analyses of eleven key questions, this book offers a unique combination of personal reflection, literature review, personal testimony, and case studies to explore these mysteries. Altogether, this text offers comprehensive explorations of the linguistic aspects of bilingualism, including who is bilingual, describing bilinguals, accented speech, and language loss, as well as in-depth examinations of personality and culture in relation to bilingualism and biculturalism, and practical discussions of speech and language processing, including language choice and mixed speech perception and production. Perfect for undergraduate and graduate students of bilingualism, multilingualism, second language acquisition, and applied linguistics, The Mysteries of Bilingualism offers an up-to-date view of the leading research questions in the study of bilingualism today.

"The Mysteries of Bilingualism is an engaging and user-friendly discussion of some of the significant issues surrounding bilingualism that have pre-occupied researchers and perplexed laypersons for many years."—Fred Genesee (2022), Journal of Multilingual and Multicultural Development "In every respect, this book is a well-timed contribution to bilingualism. It highlights some pending questions about bilingualism, which shed light on future studies to explore the unsettled issues inthis domain."—Innovation in Language Learning and Teaching "The research problems surveyed in this book offer students of bilingualism and second language learning a guide for designing their own research program, one that keeps an eye on the pending questions. Practitioners will be well served by the review of recent work that updates ongoing projects from years past."—Issues in Applied Linguistics, Vol. 23, No. 1, pp 22 - 29 "... this book should prove valuable for both novice and experienced researchers who are interested in an overall view of bilingualism or in one of the eleven issues that comprise the book."—System, Volume 111, December 2022, 102947 "François Grosjean's renowned expertise in the world of bilingualism is on display in this welcome addition to the field."—Linguist List, 34.518, 2023 "All in all, this is a rare, comprehensive overview of research accomplished, with clear pointers to research required, attesting to its author's immense erudition and lucid intelligence. It will no doubt impel even experienced researchers to review their approaches and methods."—International Journal of Bilingual Education and Bilingualism, DOI: 10.1080/13670050.2023.2237638