I work with 2x former Mexicans who are now US Citizens. You would not believe how pissed off they get about this. Go through a legal port of entry, fill out the paperwork, make your way through the established system and process, learn English. Just like they did. In fact I kind of don’t like the subject to come up because once they get started it’s tough to stop.
I used to work with a Mexican girl whose father used to yell at her for speaking Spanish.
“No, no, NO! You are in America. You are an American now. You MUST speak English!”