I can't really speak for why it is disagreed with--I personally find the claim that language is innate completely convincing. But one reason I've heard for dis

I can't really speak for why it is disagreed with--I personally find the claim that language is innate completely convincing. But one reason I've heard for disagreeing is the notion that some animals have language (not true unless you water down the definition of "language"). Others seem to think that general learning mechanisms explain the acquisition of language. I find that outrageously naive, since virtually all children acquire language (and if they're raised bilingually, more than one language), whereas even good linguists struggle to define all the rules of a language.