In German - difference between "kein" and "nicht"?

I can't figure out the difference. If I want to say "I speak no English", I say "Ich spreche kein English". When I want to say "I'm not German", I say "Ich bin keine Deutsche". But, if I want to say "not very well", I say "nicht sehr gut".... show more I can't figure out the difference.

If I want to say "I speak no English", I say "Ich spreche kein English". When I want to say "I'm not German", I say "Ich bin keine Deutsche". But, if I want to say "not very well", I say "nicht sehr gut".

I can't tell the difference between the last two phrases.
5 answers 5