My wife's Chinese. I know pragmatic Chinese. Like, "change a diaper". I also know some pretty good potty talk.
She brought her relatives over as soon as she was a citizen, and pretty much decided she never really needed to comingle with English speaking people. She is an introvert to begin with, and doesn't have many Chinese friends either.
It's kind of tough with kids, like she never speaks to them in English, except maybe to answer a homework question. My daughter has to get ESL training because between her grandparents and my wife, I am the only one they hear speaking English. I feel like she is missing out on many opportunities to take advantage of community events.
My wife doesn't understand why I have to do reading with our daughter. She(my wife) really just doesn't say the words correctly. My wife also has issues negotiating or discussing things in English. It is hard for her, because she doesn't practice. It has taken my wife a very long time to figure out the how's and why's of the way it is in the US. Like we have ovens, we bake. We bake all kinds of things potatoes, casseroles, deserts, breads, and they are good. Fortunately, my daughter discovered pizza, woo! It took a long time to explain to my wife, nine times out of ten a pizza is a red sauce with cheese, please don't make a Thai seafood pizza with fish sauce more than once, or at least master a real pizza first. She eventually, understood, but wow that was hard. She does some innovative things on occasion though, but gosh darn, I want butter. I had to DEMAND butter, but once she figured it out. "Oh! butter", sigh...