Interface language != spoken language. If you are Ukrainian you might choose an interface in Russian or English for many reasons, familiarity, quality, etc. May

Interface language != spoken language. If you are Ukrainian you might choose an interface in Russian or English for many reasons, familiarity, quality, etc. Maybe they don’t want to context-switch. For most Ukrainians, Russian is (was?) a happy medium between being a language that they understand, and a language that is well supported in localizations. I speak en-GB but I prefer an interface in en-US. Yet if you asked me to speak en-US with all its grammatical, lexical and phonological differences intact I would fail because my understanding is read-only.