Language differentiation in early trilingual development: Evidence from a case study

Current research on multilingual language acquisition is concerned with whether bilingual-to-be children build two language systems from early on or a single system comprised of elements of both languages. While several studies have shown that developing bilinguals show signs of language differentiation from the onset of speech, less work has been done to investigate whether multilingual-to-be children also start out building separate systems and whether exposure to multiple languages facilitates or hinders differentiation.; This study examines the emergence of three languages---Tagalog, Spanish and English---in a child raised in a trilingual environment and focus on the process of language differentiation from the perspective of phonology, lexicon, syntax, and language choice. The child's trilingual development between 1;4 and 2;5 is followed through diary records and recordings of her spontaneous speech in different language contexts. These data provide the ground to address the following questions: (1) Are translation equivalents, i.e. two or more words with the same meaning, one from each language, produced from early on indicating that separate lexical systems are being built? (2) Do the child's accuracy levels in the pronunciation of word-initial consonants vary cross-linguistically suggesting that she can differentiate her developing phonological systems? (3) Are argument/predicate sequences differentially ordered in Tagalog, Spanish and English indicating that the child is applying different syntactic "rules" in each language? (4) And finally, do her patterns of language choice change from interlocutor to interlocutor providing evidence for pragmatic differentiation?; The results indicate that language differentiation---in its various components---is clearly possible in early trilingual development as in the case of early bilingual development. The subject appears indeed to be building, from the onset of speech, multiple lexicons, separate phonological and syntactic systems, and distinct sets of pragmatic rules in the same manner as developing bilinguals. These results suggest that exposure to three rather than two languages neither hinders nor facilitates language differentiation and that the constraints operating on early language learning might be the same for all children, irrespective of the number of languages acquired.