It's hard for me to imagine what it's like to write code in your native language. I imagine using keywords, methods and variable names, shell commands in my native language -- it would be weird!
I was lucky, and when I've started programming I had good enough level of English.
As for the other people, usually, developers inevitably learn at least some English by reading the documentation and consuming other it-related content.
However, grammar mistakes in the code, weird comments or commit messages are not rare.
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