Okay some context,

I am a White Male educator and I work with and I am friends with three female educators (two are Black the other is Latin). The two Black women I work with are not fond of the Latin one, because she uses the N-Word despite not being Black and does so very casually. One time when I was talking with the Latin educator in a casual setting she did say it in front of me very casually. Candidly speaking, this is causing a lot of friction in our department and frankly I want to have a conversation with her. So how do I go about doing this as a White man who is trying to tell a Latin woman to not use a word that is not hers and is harming our colleagues?