The level of English varies, and salaries usually correlate with English proficiency just as well as with technical ability. I believe this is because devs with

The level of English varies, and salaries usually correlate with English proficiency just as well as with technical ability. I believe this is because devs with strong English can compete as remote workers on the global market, whereas those who are not professionally competent in English are relegated to work in firms that speak their language, or at least to have a bilingual management layer above them.