FWIW, I grew up in an Irish/Italian working-class fishing town in New England. I definitely speak differently at home vs. at work the biotech industry, and I don't mean profanity-wise, I mean accent-wise and grammatically as well. I would certainly sound "lower class" to certain people if I spoke this way at work or at a job interview. I suspect many of my colleagues who come from a similar class background would do the same.