The mysteries of bilingualism: unresolved issues

François Grosjean’s latest book, with its colorful cover carrying the simple title The Mysteries of Bilingualism, may briefly intrigue readers with just a casual interest in bilingualism or a need for practical guidance. However, the subtitle, which we first come to on the title page, hints at the author’s academic purpose, and the introduction states it clearly. He proposes to examine eleven unresolved issues concerning bilingualism and for each of them review relevant research, highlight leads most promising for their elucidation, and give ‘the best explanation we have’ (1). In his Part 1 (of four parts), Bilingual Adults and Children, Grosjean fittingly begins by questioning how the term ‘bilingual’ should itself be defined, before going on to explore how many bilinguals there might be, and how bilingual infants progress to language separation. How we understand ‘bilingual,’ he shows, has changed with time. Where forty years ago it primarily meant the ability to speak two languages, with an emphasis on fluency, nowadays attention is given rather to amount of use, so that even second language learners may qualify. Grosjean’s own favored definition of ‘bilinguals’ is ‘those who use two or more languages (or dialects) in their everyday lives’ (11, italics in original). This may seem compellingly simple and convenient, but even readers of this book may find it problematic. Indeed, in the third section of Part 1, dealing with bilingual infants and how they distinguish their languages perceptually, the tacit meaning of ‘a bilingual’ seems quite different. This is clear when Grosjean writes that ‘bilingual infants maintain their perceptual sensitivity to language differences – something they need in order to separate and learn their two languages’ (32), leading to the ‘operation of conceptual language categories’ (40) essential to language use. Even if ‘bilingual’ here is taken as shorthand for ‘bilingual-to-be,’ it denotes a distinct group of infants pre-learning, and calls for a more comprehensive definition (perhaps emphasizing ‘attention’ rather than ‘use’). Part 2, Linguistics and Neurolinguistics, examines in turn accents (their detection, their comprehensibility, and reasons they occur in one’s L2 or L3), language loss, and bilingual aphasia. The pages on aphasia, in particular, display the full historical sweep of Grosjean’s project. After citing recent neuroscientific theory on factors in bilinguals’ impairment (lesion site; impairment of the cognitive control system), he takes us back to late 19th century writings of Ribot and of Pitres to review the factors they posited as relevant to both impairment and recovery (respectively first language acquired and language(s) used the most). Other posited factors (age of acquisition of the second language, language dominance, literacy, and so on) are then scrutinized in turn in a fascinating discussion. This section also reminds us how much bilingual studies is necessarily an interdisciplinary field (citing insights from psychology on the first language acquired, sociology on language use, and neurology on aphasia). In the zone of convergence of multiple disciplines, specialists limited to any single one can find it hard to grasp the overall context of their project. The far-ranging discussion we find here depends on a synoptic view that tacitly invites researchers to venture beyond their own specialty and thereby appreciate the actual vastness of the field and full value of their endeavor. Part 3, Language Use and Language Processing, looks into how bilinguals use two languages in interaction, what bilinguals’ languages are used for, and whether language processing is selective or