So no, capable of using language is not identical to person, but neither is it very far away. It's certainly close enough to recognize that saying that "Humans and Klingons are animals" doesn't really address the question raised. WE are the ones who brought up the person-vs-animal argument of ngagh/nga'chuq as pure speculation; if you'd rather frame it as capable-of-using-language-vs-not-capable-of-using-language argument of ngagh/nga'chuq, then do so
At this point you seem to be questioning the meaning of the word people.