The true problem is, we're unintelligible to anyone that doesn't care enough to listen. Anything with different vowels and archaic grammar and pronunciation gets tuned out immediately, or the listener gets angry (which at least shows an attempt at listening).
She is of Mexican descent and grew up relatively poor in Stockton, CA. I'm of Scot descent and grew up in a relatively poor area of rural AR. We mentioned that I acquired most of my vocabulary in my teen years through reading, and as a result sometimes use words that I've never heard spoken and am therefore apt to mispronounce them. It was much more of an issue when I was younger, but it still happens occasionally. She said she had much the same experience, and called it "code switching". I had heard the term before and knew approximately what it meant, but until then had never considered that it applied to my own experience. It absolutely does: https://en.wikipedia.org/wiki/Code-switching
I'd say that it applies to Cajun and Creole as well, only more so.