How long is ‘a long term’ for sound change?

This paper investigates the adoption of ongoing community sound change by individuals by considering it as an instance of second-dialect acquisition. Four ongoing changes in Dutch, all involving the move from one-allophone to two-allophone systems, make this possible: these ongoing diachronic changes are simultaneously a source of synchronic variation between Netherlandic Dutch and Flemish Dutch. The paper investigates the adoption of these differences by sociolinguistic migrants: Flemish-Dutch speakers who migrated to the Netherlands to start their university studies. Participants were tracked over the course of nine months, using a rhyme-decision task and a word-list-reading task. Results show robust differences from Netherlandic-Dutch controls, which do not diminish over the nine months. While longer-term accommodation to these same changes has been found elsewhere, it appears that nine months is not enough time. The implications of these findings for various subfields of linguistics, particularly sound change and second-dialect acquisition, are discussed.