Are there cyrilic using people who don't know the latin alphabet? I mean in reality, not in theory.

If they didn't learn it - why should they?

Sure there is a common application in Math/Algebra and Physics (if the person reading the sign even bothered to learn and didn't forgot everything the second they stepped out) and in product/brand names in the everyday life, but there is a difference between knowing the alphabet and having a vague idea how some letters are pronounced.

Also there is enough of false friends (like `B` or `P`) to completely jumble the pronunciation and consequently fail the understanding.

I didn't know that. We have a strong support for Welsh speakers here but despite that the last person not capable of speaking English has already died many years ago. I imagined it might be the same for Russian people who don't know the latin alphabet since it's taught in school now and everybody goes to school nowadays.

Welsh and English are both use Latin alphabet so it is not quite the same idea.

Russia has an almost mandatory foreign language in their education[0], which is a subject to availability I suppose - if there is no one who can teach the language in some remote village then nothing can be done, though with all that COVID measures I suppose the idea of remote learning is there.

But again, it all depends on the quality of education, the abilities and the will of the student and not being forgotten. People who don't use another language would almost completely lose it in 3-7 years even if they had A+ for it in the school.

Though it all more applies to an older generations, I think, because younger ones should be explicitly exposed to the Latin alphabet through the keyboards of their computers and smartphones, in Instagra/TikTok handles, email addresses and so on.

[0] https://en.wikipedia.org/wiki/Unified_State_Exam

> Welsh and English are both use Latin alphabet so it is not quite the same idea.

I am also notice[sic] stuff:

> are both use