English speakers: Need help explaining problem with "get better my English" A friend said "I need to get better my English" and I corrected him by saying he should use "I need to improve my English". He asked why he cannot use "get better" in this case.

I'm not a teacher, or great at grammar in general,  and I really had a hard time explaining the reason. Can anyone provide a clear explanation that I can pass on to him? I hate not being able to help.