Abstract
Based on the Literature of SLA that highlights the possible transfer of explicit and conscious knowledge of L2 into implicit, spontaneous and subconscious knowledge, this article reveals, from a psycholinguistic perspective, that any difference in L1 and L2 production in bilinguals’ communication is determined by the linguistic knowledge available in the two languages. This study investigates how and when Bilinguals code switch to L1 as the language of identity and expression, and how professional interpreters employ explicitness from L1 into L2 and implicitness from L2 to L1. The findings reveal that L1 is considered more spontaneous than L2 although the latter could be produced fluently and accurately in different communications. This article considers the bilinguals who have their L1 as a mother tongue, but L2 as a foreign language, i.e. learnt later after L1 is acquired. As L2 could be less spontaneous, it means that it is not totally implicit and subconscious as the mother tongue. However, as L2 could be produced fluently and grammatically, it is said to include implicit and explicit/ thinkable knowledge and that the two types of knowledge could interact to exist in L2 production by such users. This conclusion, therefore, advocates the weak interface position of implicit/ explicit knowledge in second language acquisition, i.e. users of L2 could not develop a completely L2 implicit knowledge. Rather, explicit knowledge could exist alongside the procedural/ implicit knowledge in L2 production.