Comment 10 by ANTIcarrot :

"But Terrace concluded that that the animal was merely imitating his trainers or using the phrases to get what he wanted, rather than actually constructing sentences as a human child would."

Not to put too fine a point on it, but how is 'using phrases to get what he wants' any different from what everyone does?

And where exactly does this leave those human children who for various reasons never develop the mental capacity to construct their own sentences?

There is a crucial difference. Its a question of whether the chimp has actually learned language, i.e., the ability to construct sentences to communicate information. Chomsky and others believe that the capacity for language is hardwired into humans, that we are all born with an ability for language that other animals just don't have. Chomsky's critics say that other animals can learn language and that it was only the human ability for sophisticated speech that enabled us to have langauge. Hence the idea to teach chimps sign language.

I think its a mistake that both sides make to equate this with some kind of moral evaluation. As if saying that chimps are or aren't capable of language makes them more worthy of moral consideration or alternatively diminishes the specialness of humans.