"Charles Darwin spotted it. In The Descent of Man, he wrote: 'The formation of different languages and of distinct species and the proofs that both have developed through a gradual process are clearly the same.' He'd been struck by ideas that William Jones had advanced 50 years earlier, that the similarities between languages as disparate as Sanskrit, Latin, and Old Persian, suggest a common historical ancestry."
Says the first paragraph of an article in The Scientist Magazine for Dec 20th 2004 p 16. What an excellnet introduction to the work being done linking Linguistics with Evolutionary Biology. It shows how one theory can help in explaining another in a synergistic way that enlightens both to the benefit of Science in general, and the understnding of how we aquire language in particular.
I'm no linquist, but I do remember reading Chomsky's book On Language some time ago, and I think I understood the basics, at least that we all seem to be born with some inate basic grammar (Universal Grammar) that allows us to pick up our parents language rather quickly, regardless of where we are born, which culture, etc. This article tells us that liguists are now looking at the biological reasons for this, requiring co-operation between these two previously unrelated field.