Maturational constraints on child and adult SLA

Claims for a biologically based schedule for language learning were first advanced 50 years ago. 100+ studies later, debates continue as to the existence, scope and timing of one or more sensitive periods for SLA. At least eight reasons can be identified for the lack of consensus, several of which appear to be without basis. They are discussed, along with ten more positive developments over the past decade, including research into the possibility that the very few learners who achieve near-native L2 abilities do so because of superior language learning aptitude(s).