Abstract: An important question in research on bilinguals is whether bilinguals activate information in both languages even when they intend to speak in only one of their two languages. Psycholinguistic and neuroscientific investigations have provided inconsistent data regarding activation of the two languages by using explicit task paradigms. However, most prominent theories of bilingualism assume that mental representation of languages can be divided into a lexical (word form) and a conceptual (word meaning) level. Thus, the notion of activation was ill-defined in previous studies and it is unclear to which degree words from the non-target language are processed by bilinguals. Therefore, innovative paradigms, conceptual decision tasks and lexical decision tasks were designed in this study to further explore the activation and inhibition of non-target language in bilingual speech production.
In the present study, we used the task of cross-language repetition priming. Participants from South China Normal University included sixty students of non-English-majors who did not pass CET Band 4 and forty students of English-majors. All participants were Chinese natives aging 18~25 years, who learned English as a second language from about the age of 11. Participants were randomly divided into different experiments. Each experiment consisted of a study block and a test block. In the study block, bilingual participants named the pictures in the target language, and in the test block they were instructed to make a concept decision (Experiment 1 and 2) or a lexical decision (Experiment 3). Non-target language words were presented in the test block and half of their translation equivalents were used in the study block. Some new words never used in study block as fillers appeared in test block. Then, Study status (studied vs. non-studied) was manipulated in the test block. The response times and accurate rates were recorded.
In experiment 1, there was no cross language repetition priming effect in both highly proficient and less proficient bilinguals. But in experiment 2, we observed cross language repetition priming effect with conceptual decision tasks only in less proficient bilinguals. However, no cross language repetition priming effect was found with lexical decision tasks in experiment 3. The results revealed that for highly proficient Chinese-English bilinguals, the non-target language was inhibited on conceptual level during the speech production. But for less proficient Chinese-English bilinguals, the non-target language could be inhibited on conceptual level only when using the more dominant language; while using the less dominant language, the non-target language was just inhibited on lexical level but not on conceptual level.

Key words: speech production, non-target language, activation, inhibition, repetition priming