Seeing as my Russian, Ukrainian, Belarusian, Mexican, French Canadian, and Brazilian coworkers don't seem to have these issues with me I don't think the issue is with my explanations.

Sorry I didn’t mean you specifically, rather you as an English speaker

Funny, when I was in the US, my Russian, Ukrainian, Chinese, Mexican, French, British, and 99% of the American coworkers had absolutely zero issues with my Indian accent, except that one American guy who would ask me to keep repeating even though the rest of the room had already understood and processed what I said.

The problem likely lies deeper than just the accents; and by the way, the English requirement (including a verbal test) is already set in place for most of the workers. The regular halfway-decent ones will likely already have TOEFL scores hovering around at minimum the high 100s, and in the non-university hiring pipelines I have seen, the English/ESL tests seem to be common if you are not from an English-speaking country, so if you are seeing people where nobody can understand what they are saying, you need to take a better look at your employer's hiring practices.