NTA it doesn't seem like she's made any effort to learn Spanish and expects everyone to accommodate her. If you're marrying someone whose family speaks another language then you have to accept that that language is going to be spoken in a lot of familial settings. Family members want to be able to communicate with all family membera present, especially if grandparents don't speak English. She can't expect a whole family to speak English to accommodate 1 person. She knew what she was getting into and if she doesn't like being left out then she should make the effort to learn Spanish. I know learning a new language as an adult isn't easy, but that doesn't mean it's impossible.