The manner in which children of diverse cultures and varied circumstances acquire language is extremely uniform. Children of accomplished academics in Cambridge pick up English at the same rate at which children of illiterate farmers in Benin pick up Gbe. They will hit the same milestones at the same age.

We also know that a stroke can seriously impair a person's ability to use language, even as their memory and powers of abstract reasoning are otherwise in tact.

The only way to make sense of that that I know of is to suppose that language engages some sort of specialized structures within the brain.

If such structures exist and are implicated in the acquisition of language by children across different cultures, then language must not be infinitely plastic. There must be certain structural properties that languages share that allow them to be acquired in such a regular, programmatic fashion.

Is this conclusion unwarranted, unreasonable, false, or dubious? Are there other ways of making sense of these phenomena?