How does the language acquisition period affect simultaneous interpreters’ language processing?

This study aims to identify the similarities and differences in cognitive-psychological semantic (Translation Equivalent) mapping employed by early, and late balanced bilinguals at the adult level. The subjects of lexical-semantic recognition tasks were limited to fourth-semester learners at graduate school of interpreting and translation to analyze the effect that the L2 acquisition period (or Age of Acquisition, AOA) and immersive education may have on cross-language processing among highly-proficient bilinguals. The experimental words were composed of non-cognate abstract words with two levels, and in four language directions (L1 > L1, L1 > L2, L2 > L1, L2 > L2) to compare monolingual, and bilingual priming effects. Early, and Late Balanced Bilingual groups (i.e., EBB and LBB) were comparable in many ways. However, mid balanced bilinguals who had exposure of more than six years after the critical period showed distinctive features. With a low lexical difficulty in the L1 to L2 direction, Mid Balanced Bilingual group (MBB) showed a similar tendency with EBB, while it was analogous to LBB when the lexical difficulty was high, and the language direction was from L2 to L1. Such results can be interpreted as evidence against the critical period hypothesis, indicating that language dominance may change due to the L2 acquisition period and immersive education. In contrast to their subjective perception, the mother tongue of all subject groups turned out to be Korean since all subjects, without exception, were faster in deciding words from English to Korean. The parental factor was limited to be all Koreans in order to control biological differences, from which the parental factor is reversely inferred most influential for early balanced bilinguals’ language dominance.