ABSTRACT
While in previous chapters the focus was first language development (Behrens, van Geert) and first and second language development (Unsworth), this contribution will focus only on second language development (SLD) over the lifespan. In our view, second language acquisition is a process that is clearly related to the development of the first language. Following earlier suggestions by Cook (1995) and Herdina and Jessner (2002), we take the position that the language system is an integrated system consisting of languages, dialects, styles and registers that all interact. SLD is basically the development of the multilingual system over time. This view also implies that language acquisition and language attrition are manifestations of similar mechanisms of change, and the multilingual system can develop in many different ways, not only through the acquisition of new languages or dialects but also through the decline of language skills due to nonuse or injury. In line with Behrens’s and van Geert’s contributions, our view on SLD is usage-based. To explain this further, changes in the system are the result of changes in language use, and the other way around: use is change and change is use (Larsen-Freeman, 1997).
