In the last few years, systematic research on third language acquisition has gained momentum and attracted increasing attention as a crucial part of the wider field of individual multilingualism. The studies presented here zoom in on the acquisitional activities of the individual learner and the patterns of crosslinguistic influence which arise in the multilingual setting.

WHY A THIRD LANGUAGE PERSPECTIVE?

Non-native language acquisition has for the most part been studied in terms of foreign or ‘second’ language acquisition (SLA). Even if it is understood that learners often know more languages, the possible influence of prior non-native languages on the process of acquisition has in the past been assumed by most SLA linguists to be insignificant, and hence usually disregarded. The learner's first language (L1) was the only background language to which attention was paid. In this tradition all cases of non-native language acquisition were analysed as second language (L2) acquisition, and no difference was made between a previously monolingual and a bi- or multilingual language learner. The concepts of L2 and SLA came to cover non-native languages generally. The upcoming focus on third language (L3) acquisition means that researchers have begun to differentiate learners according to the complexity of their linguistic background.

There are a range of reasons for the interest in L3 acquisition. For the sake of the discussion we may distinguish practical, theoretical and empirical types of motives.