Does language define our identity?

Language can define a person's identity but I think it depends on the person. My dad being bilingual, to me he has two different identities. When with my mom's side of our family or just English speakers in general my dad is not as loud and speaks slower, still just as friendly but he is a completely different person when he speaks Spanish. When he speaks Spanish he seems to have a lot more pride, is a lot louder, laughs and jokes around a lot more. But language can also be a restriction on ones identity which means that language does not necessarily define a person's identity. A person maybe not as well educated as someone else probably uses weaker language than someone with a very good education but just because they don't speak as eloquently as a well-educated person should not make them defined as "dumb" like most people would. So language can define a person's identity but not necessarily.