[Tainnor]

Fair, I just looked for the first reference I could find. I haven't done any real linguistics in years, although I vividly remember the arguments. Especially that Evans & Levinson article 10 years or so back ("The Myth of language universals") which generated quite some heat. If I have time, I will check out your reference.

Not sure about the negative examples; but language acquisition was never my focus area anyway.

I would just generally be cautious about applying formal language theory too readily to linguistics, that's all I wanted to say.