 There does not really seem to be anyone who is a complete non-nativist: nobody really thinks that a creature with no unlearned capacities at all could acquire a language. That was the point of the much-quoted remark by Quine (1972: 95–96) about how “the behaviorist is knowingly and cheerfully up to his neck in innate mechanisms of learning-readiness”. Geoffrey Sampson (2001, 2005) is about as extreme an opponent of linguistic nativism as one can find, but even he would not take the failure of language acquisition in his cat to be unrelated to the cognitive and physical capabilities of cats.