Absolutely, and I would take jargons as an example. American Legal English is a kind of English, but it's not "real" in the sense that there are ideas in English that it can't properly express, and vice versa, and even skilled legal practitioners frequently make inconsistent mistakes. This is predicted by the fact that it is learned in adulthood; the language has no native speakers. Conversely, among languages spoken from birth, we expect and find that they are internally consistent and of roughly equivalent expressive value.