[0x457]

Unless they're using a programming language that isn't English-based (for example, Russian 1С system uses Russian keywords and the whole codebase is usually in Russian), then most of the code stays English.

This way, you don't have to change keyboard layout while writing code.

Anyway, you're forced to learn some English when doing any real software development.

[kdmtctl]

Anecdotally, a lot of 1C developers are not proficient in anything else because they don't need English in the main field, platform docs included, and can only get scarce translated versions of anything else. And blogs in Russian, which are not plenty and not always correct.

This makes some of their infra work and common misconceptions a little bit ... esoteric. So, English is crucial not just to do the job but to get best practices and CS info in general. It really helps a lot.