YTG123

The military censor in Israel does the exact same thing: ostensibly to prevent enemies from using the data to improve their systems, in reality as an attempt to keep domestic morale high (it only ever manages to slow down the inevitable fall, though).

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.