It was designed in a time where keyboards around the world (German QWERTZ, Cyrillic JCKUEN/ЙЦУКЕН) and text encoding (remember that this is pre-Unicode, so we're dealing with ISO 646 and Eastern Asian character sets) has only the subset of Latin characters used in the US. Nowadays, it is strongly recommended to simply use the standard American keyboard in programming (outside of comments).
I still cannot decide whether it's better to comment in English or in my native language. English works, but it's a weird fit with words from the application domain. Those, I don't really want to translate, but I have to keep doing it because there is so much legacy code with the translations. Sure, I could do a rampage through the code base and fix everything up (would be done in an afternoon thanks to IntelliJ), but my team would almost certainly give me lots of flak for this. At the same time, it also feels weird to conjugate english words in my native language.
https://en.wikibooks.org/wiki/C_Programming/C_trigraph