The most conspicuous object of Second Language Acquisition (SLA) research is obviously “second language acquisition”. Unfortunately, however, the nature of this object is far from clear, and different researchers have given very different interpretations of it. Read the following statements, all of which refer to points relating to the meaning of the term “second language acquisition”.

I. – “Second language” refers exclusively to somebody's foreign language learnt after his or her primary language has been acquired. If he or she then goes on to learn still another language, this language will not be considered “second”; rather, it will be referred to as his or her “third language”.

II. – The difference between second and foreign language is merely terminological in essence, with some researchers favouring one term, some the other. There are no radical differences in terms of what is learnt nor how it is learnt.

III. – A distinction is made between “naturalistic” and “instructed” second language acquisition, according to whether the language is learnt through communication that takes place in naturally occurring social situations or through study, with the help of reference books and teachers.

IV. – Researchers have been unable to agree on the definition of what is meant by the term “acquisition”. For some, it will be different from “learning”, while others do not see any substantive difference between them. Also, a distinction can be made between acquisition as “emergence” or “onset” of a linguistic feature and acquisition as “accurate use” of it.