I have a colleague who is very new to this country (USA). His English leaves a lot to be desired, to the point that it often actually hinders communication. I think he's trying to learn, but it's obviously hard.
Sometimes in an email, there will be a few mistakes that are fairly glaring, even if I get what they're trying to say. I was considering asking him (so as to not just give unsolicited advice), "would you like me to correct any errors in your writing I see when you email me? It could help you improve more quickly."
It could definitely help him learn, but I'm also aware that it could be embarrassing for him, as well as presumptuous on my part. Personally, I (like to) think I'd really like it if someone made me that offer if I were in that position, but of course I can't know for certain.
Is that a good idea, or is it better to just mind my own business?