YTG123

Yes, but it’s usually very subtle (e.g. in realizations of single phonemes or in intonation). There are also more extreme cases which other commenters have pointed out.

I recommend you look up sociolects and sociolinguistics.

Not necessarily of two-party systems or FPTP, I think this is a property of single-member districts in general. If you have multi-member districts (say 4 or 5 representatives per district) this becomes much less effective. Statewide PR solves this by removing districts, which for most people isn’t ideal.

Homo ignorans :)

School teachers. Not deliberately, but there is a shortage of them here.