For background, me and my mum do not have the best relationship to put it lightly. We muddle along okish for most of the time as long as I keep quite superficial and not engage/end calls when she starts with her bs. She's ok for a while but her ways of thinking always rear up their ugly head.
OH is English, I am not. I'll be honest, I was rather lazy about speaking in my language at home , then she had some SALT issues and my priority was to be understood and be able to communicate properly with her English dad, at school, with her friends etc.
As she grew up, there was another reason, which became more and more important. To protect her from my mum's comments and views , while still allowing them to have a close, loving relationship . That was great when she was little , but she naturally distanced herself a bit as she grew up (teenager now).
My mum is very resentful she can't talk to DD and is always on my case about it, from pitiful "poor me " stuff to petty , vindictive and pointless stuff like " well if she doesn't learn x I won't love her anymore". I just shrug it off or take the blame on being lazy and uncooperative.
Recently we were on a call and she made some disparaging comments over DD's weight (who is a healthy weight according to the NHS) , as she has some very set ideas about weight , with the added disappointment of having a fat daughter. I snapped and I told her this is exactly why I haven't taught DD our language , so she wouldn't be exposed to stupid and toxic comments.
That of course , did not go well. I switch between feeling guilty (because I upset my mum) and being oh well, it is what it is , and she created this situation by being who she is.