“Research findings The ‘Teach what is teachable’ view suggests that while variational features of the language can be taught successfully at various points in the learners’ development, developmental features are best taught according to the learners’ internal schedule. Furthermore, although learners may be able to produce more advanced forms on tests or in very restricted pedagogical exercises, instruction cannot change the ‘natural’ developmental course. The recommendation is to assess the learners’ developmental level and teach what would naturally come next.”