It hasn't been proved one way or the other yet.
I think the instruments to learn language are hard-wired into the brain but the language itself is acquired through interaction.
I’d say for someone language, any language, is hardwired in the brain, and thus with just little practice it manages to learn it well. So as Julia said: “the instruments to learn language are hard-wired into the brain” some have it more developed and some less, but practice is the only way for those with the less developed one.
The idea is that universal grammar, not specific, is hard-wired.
Our ability to communicate, or get thoughts across for others to understand, is hard-wired. Language is not necessarily.
The human brain can *process* complex information but it can't *generate* complex information.
In the sense of "innately (genetically) determined" language is hardwired into our genes, I believe