Saying that someone doesn't know their own language is tricky. First, for a huge amount of people in South America, Spanish isn't the language of their past. Se

Saying that someone doesn't know their own language is tricky. First, for a huge amount of people in South America, Spanish isn't the language of their past. Second, defining "knowing" in this binary way is also problematic. It's a continuum, where each express along this continuum what they need (or desire) to move through their day. So I don't disagree that someone, though a native speaker of Spanish, may not be able to understand Italian, but I don't think it's right to say that they don't know the language. Edit: typo