I recall when my youngest was a science student at a state university in the 70’s, she complained to us that the lab work was very difficult in that the instructors were difficult to understand as they were ALL foreigners and spoke poor English..
I can relate as I was a chemistry major. Most of our lab assistants were graduate student foreigners.
One in particular I don’t think understood any English at all. He was a pleasant Chinese kid. He would always answer a question by thinking for a moment, then saying “yes” with a smile. Nothing more.
Being the rascal that I am, one day I decided to test him. I asked him a nonsensical question: “After I turn in my lab report, can I melt all the beakers at my station?”
He thought for a moment. “Yes”.