Indigenous dialects

Greetings from Arunachal, I'll just get into the point, I'm curious, when people from different tribes in Mizoram marry, do their kids typically learn multiple tribal dialects, say Mara (mom's side) and Hmar (dad's side), along with Lusei? Or do they usually end up speaking mainly Lusei and become non-fluent in their parents' dialects? I'm asking this cause In Arunachal, I've seen many "cocktail" kids speaking mainly Hindi and a bit of their parents' dialects –but not fluently because obviously both the parents don't know each other's dialect , so they rely on hindi for communicating and the kids as well ends up speaking Hindi and broken tribal dialects or sometimes they just don't know at all, I'm wondering if it's similar in Mizoram.? How do you guys handle that?