It's not that the parts responsible for language couldn't be repurposed for something else (although I don't know whether it's true). It's the fact, that more g

It's not that the parts responsible for language couldn't be repurposed for something else (although I don't know whether it's true). It's the fact, that more general learning skills cannot substitute dedicated language learning capabilities. It's hard to come up with different hypothesis once you know that children not exposed to language at all for some time (up to 4-6 years, but I don't remember) lose the ability to acquire it forever.