I wish i understood what my grandparents said... fukk my parents not teaching us the language...
You the 3rd person I've heard of dealing with this. It's the most illogical shyt ever.
My niece and nephew are going through it now..But, tbh, although it's the parents' fault I don't even harbor any hard feelings.
It takes a lot to teach a language and unless some1 is home all the time to do it, or they don't know English and only speak the native tongue the kids won't get it.
I would go through this. I'd try to teach them Spanish but that shyt is super time consuming. And kids aren't receptive to that. Especially when they know that they can just talk to you in English and be understood.
My strategy will be to never talk English around my kids. I'm just going to be a foreigner to them.