As it so happens, I have a Slavic sister-in-law who came over here on a green card and eventually married my brother. When I first met her, her English was pretty sketchy.
In the twenty plus years she has been here, she managed to obtain a masters degree for which she had to write a theses. She now teaches her specialty at a small state college.
She also is fluent in five languages. What is more amazing to me is that 95% of the time, you would never be able to tell she wasn’t born here. Not only does she have practically no accent, she has all of the idioms down.
Could she have accomplished all of that without good English skills? Perhaps people who marry billionaires are more insulated from the effects of less than perfect English skills.
But for most of the rest of us, they are crucial. Anyone who says that heavily accented, and ungrammatical English is not a severe disadvantage in the job market, probably is only used to hiring janitorial staff.
I am also a volunteer literacy tutor who works with ESL students. I know of what I speak.
And this will be my last comment on this thread.
Everyone is different.
Don't be judgmental. You don't know the each individual's story or person. You just think someone should behave, act and talk like you demand. Life does not work that way.
Henry Kissinger has been in the US for almost 80 years, and he still has a thick German accent. I don't recall Kissinger being ridiculed for his accent; maybe for some of his policies, but that's a different matter.
It depends on the individual.
I know older German women who were war brides, came over here in the late 50’s and early 60’s. Many of them have had successful careers and though they speak English well they still have a heavy accent and speak with some non-standard English phrases.
Others immigrants I have met speak English with no accent at all but if you read something they write it is clear that English is not their first language.
I don’t think it’s that big of an impediment to have an accent. We have many non-American scientists, engineers, doctors etc. working in this country at highly technical jobs who still speak with accents from their country of origin.
Yes, you do need to be able to communicate but I don’t think you need absolutely perfect English diction to be able to do that. It certainly helps but there are other factors as well such as one’s competence in a given field.
For example we had many German and Polish scientists who immigrated to the US after the war who never spoke perfect English but who nevertheless did valuable work.
I have worked with many people who have strong foreign accents and it doesn’t seem to keep them from getting hired.
Where it does make a big difference is in written language. To be able to write perfectly in a second (or 3rd, 4th) language is very difficult. Very few can master that. But then many people who are native English speakers cannot write well in English.