Effect of age of acquisition on concept mediation in heritage Arabic bilinguals

Currently accepted models of bilingual lexical retrieval posit a single conceptual domain and two language-dependent domains for all bilinguals. Of particular interest is how the second language domain interacts with the first language domain and the conceptual domain; the L2 domain is either directly attached to the semantic domain or instead mediated by the L1. Research suggests that for highly proficient bilinguals, newly acquired words attach to their conceptual connotations directly; conversely, for beginning L2 learners, the words of an L2 lack a direct connection to this semantic information and, instead, are only accessed via L1 translation equivalents. This means that for beginning L2 learners, the words of the weaker L2 can be accessed only by translating from the L1. As the learner becomes more fluent in an L2, words in that L2 begin to be directly associated with the semantic information and are retrieved without mediating through the L1. This lexico-semantic model has been used by researchers to describe most types of bilinguals. Problems arise, however, when applying this model to heritage speakers, a population of bilinguals who learned one language in childhood but have lost fluency by adulthood. The model suggests that heritage speakers would not be able to retrieve semantic connotations from their heritage language without translating it from their second, now-dominant language. A second, though conflicting, option is that the L1 remains conceptually mediated, but those links are weakened and effectively non-functional. This would suggest that heritage speakers’ two language domains have effectively independent access to the conceptual space. I hypothesize that simply having proficiency in a language cannot be the only reliable guarantor of word-to-concept connections; instead, I propose that the age at which a language was acquired must guarantee a semantic connection even more reliably than proficiency can. The present chapter disentangles the respective effects of age of acquisition and language proficiency on developing concept mediation. In this study, 11 heritage Arabic-English bilinguals with varying degrees of Arabic proficiency were administered a picture-naming task and a translation task. The findings reveal heritage speakers’ response times generally match the predictions of the concept mediation model irrespective of proficiency, with the exception of extremely low proficiency speakers. Therefore, for all but extreme cases of language loss, having learned a language in early childhood even without having reached full fluency is enough to assure semantic connections in adulthood.