I listened this morning to a radio discussion about accents (French radio France Inter, Doit-on avoir honte de notre accent ?). It was about accents from various regions in France (and abroad) and how people are discriminated if they do not have the "official accent" (equivalent I guess to the BBC or Queen accent in the UK).
When discussing that afterwards over breakfast, my son said that people should speak in a way which is understandable by others. To what I said "do not make the confusion between having an accent and having a bad pronunciation".
And then I started to think about my comment. I ended up with the conclusion that I actually do not know if there is a difference. After all, an accent is an agreement between a group of people about how to pronounce words (and rhythm, ...)
So my question: what is the difference between having an accent and having a bad pronunciation. Could the latter ultimately evolve into the former if more people do it?