Linguistic and cognitive mechanisms in foreign vocabulary acquisition .

摘要

The general goal of this dissertation research was to examine linguistic and cognitive mechanisms in foreign vocabulary learning within theoretical frameworks of working memory and connectionist word processing models.; In Study 1, the effect of bimodal (auditory-and-visual) vs. unimodal (auditory-only) presentation on foreign word learning was examined at different levels of cross-linguistic overlap. Monolingual English-speaking adults were randomly assigned to one of four foreign-language conditions, where the overlap in phonological and orthographic properties between the foreign language and English was manipulated orthogonally. Results revealed that bimodal learning improved retention of foreign words that matched English in both phonology and orthography, but hindered retention of foreign words that mismatched English in phonology, orthography, or both. Findings suggest that bimodal exposure and cross-linguistic similarity interact to influence foreign word learning.; In Study 2, the effects of two different types of language-learning experience on foreign vocabulary acquisition were examined. Foreign-word learning performance was compared across monolingual English speakers, English-Spanish bilinguals, and English-Mandarin bilinguals. Compared to monolinguals, both groups of bilinguals were more accurate at retrieving newly-learned foreign words, suggesting that bilingualism is generally advantageous for further language learning. However, within each bilingual group, different patterns of performance were observed. Findings suggest that language-learning experience can modify subsequent language-learning processes, and that a particular bilingual experience influences subsequent language-learning in specific and consistent ways. Exploratory follow-up analyses also suggest that the bilingual advantage for foreign word learning is mediated by age-of-acquisition and proficiency in the second language.; Together, the two studies contribute to cognitive models of language processing and working memory, and suggest that long-term knowledge associated with native-language letter-to-phoneme mappings influences foreign word learning, and that the language-learning process can be modulated by linguistic experience. The dissertation findings also offer practical suggestion for structuring ESL curriculum, and for planning speech-and-language treatment with bilingual clients, and can be used as guidelines for choosing the preferred teaching modality during early stages of L2 acquisition, for determining the age for L2 exposure to maximize the bilingual advantage, and for selecting the cognitive skills to target in speech-language treatment with L2 learners.