most important and useful sentece in all languages

[Kitty]

in Croatian, it's

Ne govorim hrvatski (I don't speak), ne pričam hrvatski (also) or ne razumijem hrvatski (likely the best one, meaning I don't understand Croatian)

This is one of the languages that is read phonetically, so if you don't know how to say a letter just consult that phonetic alphabet they made for airplanes (Alpha, Bravo, stuff like that). Č is read as ch.

[fija]

Beware of , in russian!

Oh, haha, I actually have this written in my notes with a coma I must’ve forgotten about it. But thank you for pointing it out! I need to be more careful so I don’t make a grave mistake in the future

[RanVor]

(Sorry for using forbidden necromantic rites on this thread.)

any polish person here? to give me the "I don't speak polish"?

If it's still relevant (probably not, but eh), both "[ja] nie mówię po polsku" and "[ja] nie znam polskiego" are correct, the second one being perhaps more useful due to being easier to pronounce for foreigners.

[Kiran]

This should go well..

I could add to the list. The below senteces mean "I cannot speak _________."
:india: (Telugu): Nāku Telugu mātlāḍaṭam rādu.
:india: (Kannada): Nanage Kannada mātāḍakke baralla.
                                   (or)
                           Nanninda Kannada mātāḍakkāgalla.

(Of course, these two languages themselves are written in scripts which looks similar to Georgian because of the curves involved.)