Dewi is not alone. Many English learners achieve
impressive fluency without an equally high level of
accuracy. Persistent errors like Dewi’s in long-time
language users have sometimes been labeled
fossilization, or the cessation of language learning
before a point of high proficiency is reached (Selinker,
1972). Fossilization may occur in immigrant popul-
ations because the pressure of work leaves no time for
formal language study, or fossilized errors emerge when