<p>Mmm… lots of my TAs at a large research university didn’t speak English that well. And many (not all) were teaching as a way to fund their PhDs so they could become researchers. It wasn’t always an option to “TA hop” for help, they wanted us to go to our own TAs, and some of them covered the material at different paces and depths. And many of the professors were busy with grad students and their own research, and weren’t going to spend a lot of time with undergrads. I don’t get the impression that things have changed much in those environments…</p>