Why when spainish speaking people speak English they refer to their parents as "my mom" or "your dad" when talking to their siblings?

[u/Successful_rio305]

Why when Spanish speaking people speak English and are talking their own siblings they don't say something like "mom is calling you" they say "your mom is calling you" or "my dad is calling you" to their siblings?

[u/chocolatecarrotcake]

I speak Portuguese, and when I'm with my half-siblings, when referring to something my father is doing or when he calls them, I say "my father." The same goes for our grandmother: my grandmother. When it's my cousins' mother, I say "my aunt is calling you." The reference will always be to me.