Second Language Learning as a Bilingualisation Pro...
Cognitive psycholinguistics theories and relevant researches on the development of bilingualism show that learners’base language plays an active role in language learning(Roberts and Kreuz，2015).The acquisition of base language is usually accomplished by exposure in natural settings，while the learning of target language takes place mainly in the classroom.Therefore，when second language learners begin to learn the target language，the base language is often，consciously or unconsciously，used for reference.
In recent years，researchers have advocated that learners’base language should be used as a resource in the teaching of second language in a moderate and principled way.Widdowson pointed out that foreign language or second language learning is no longer seen as an entirely monolingual undertaking but rather a bilingual one:“...the notion of a second language implies the existence of a first，and you cannot recognize what is foreign in a language without relating to another which is familiar，and，of course，for different groups of learners the second language will be foreign in different ways.So as soon as we accept that the subject we are teaching is a foreign language，then at least one other familiar language(typically the L1)is necessarily implicated.In other words，the very subject we teach is，by definition，bilingual”(Widdowson，2003).In his view，second language is seen as co-existing with the first language in learner’s minds，that is to say，language learning becomes a“bilingualisation process”.According to Widdowson，monolingual teaching and the bilingualisation process contradict each other，which is not conducive to the development of second language ability.Hence a bilingual approach to second language learning is recommended as the base language supports the learning of the target language.
Cook also questioned the theoretical basis for the avoidance of the base language in the target language classroom and called for a re-examination of the monolingual view based on the argument that“...the justifications for this rest on a doubtful analogy with first language acquisition，on a questionable compartmentalization of the two languages in the mind，and on the aim of maximizing students’exposure to the second language，laudable but not incompatible with use of the first language”.According to him，learners’base language should be treated as a resource and used for several functions，such as“for teachers to convey meaning，explain grammar，and organize the class，and for students to use as part of their collaborative learning and individual strategy use”.Cook argued that“the first language can be a useful element in creating authentic L2 users rather then something to be shunned at all costs”(Cook，2001).
Cummins similarly challenged the compartmentalisation of languages，which he found was premised on the“two solitudes”assumption.The pedagogical implication of this assumption is that second and foreign language instruction“should be carried out，as far as possible，exclusively in the target language without recourse to students’first language(L1)”(Cummins，2008).He argued that this approach has minimal research support.
Butzkamm and Caldwell have been strong advocates for the value of base language and stressed that it is a resource for second language learning rather than an obstacle.They argued convincingly that“monolingual lessons without the help of the mother tongue are extrinsically possible，however，monolingual learning is an intrinsic impossibility”(Butzkamm and Caldwell，2009).In the process of second language learning，learners build on existing skills and competencies in the base language to master the linguistic facts and skills of the target language.The use of the base language not only makes up for the limited time and exposure of the target language in classroom learning，but also serves as a learning support activity to improve the communicative competence of the second language learners(Butzkamm and Caldwell，2009;Butzkamm，1998，2003).