Research on first and second language acquisition found that both first and second language learners follow a pattern of development. Rod Ellis (1984) outlines three developmental stages: the silent period, formulaic speech, and structural and semantic simplification. The most interesting is the silent period, that is the first stage, when the learner is mostly listening and trying to understand and not yet talking.
In case of second language learners, usually instructors require the learners to talk even in this first stage. If the silent period contributes to the second language learners or not is controversial. However, research has shown that if second language learners could, they would be silent for some time before taking the risk of speaking in the second language.
The findings in the research on comparison of the first and two language acquisition are very interesting, and I confess I never thought so deeply in the differences and similarities between them, even having studied three foreign languages and having observed two children learning to speak their first language.
Another topic I found very important in the comparison of first and second language acquisition is the role of the input. Stephen Krashen (1982) presented the Input Hypothesis, which states the learner has to receive comprehensible input to acquire language. The Hypothesis also states that "input should be slightly above the level of the language learners. Only in doing so can the second language learner move forward." (Krashen, 1982). This theory argues that the second language learner (as well as first language learners) should be exposed to the target language as much as possible (Ellis, 1994; McLaughlin, 1987).
I wonder how to measure the level of this exposure when the second language learning occurs in a classroom setting. I agree that the input must be comprehensible. However, in the first days of contact with a foreign language, the learner will understand very little or nothing if the class is all conducted in the target language. So, if to speak only in the target language would get the learners used to the language, I think at some point of the class it is useful to provide instruction in their native languages. Not only useful, but crucial to make them engage in the activities.
Even though, I agree that the input should be slightly above the level of the language learners. This is connected to Vygotsky's theory of the Zone of Proximal Development. According to this theory, it is important for the learner to be challenged, so they can ignite their emerging capacities. Of course, this challenge cannot be unbearable; in case it is too hard, instead of trying to solve the new problem by investigating or asking for collaboration, the learner would have his motivation decreased.
It is still difficult to me, as an instructor, to find the perfect level of immersion in a second language in the classroom the learners need to keep motivated (understanding what I say in the target language) and to be challenged by the foreign language unknown vocabulary and unusual word sequence.
IPEK, Hulya (2009). Comparing and Contrasting First and Second Language Acquisition: Implications for Language Teachers. English Language Teaching. www.ccsenet.org/journal.html.
