what is the difference between?

may you help me?
would you help me?

thanks

The difficulty with phrases of the form "____ you help me" is that they tend to be idiomatic. Here is a list of some of these phrases and their meaning in AE.

"May you help me" means "Are you allowed to help me" and would not normally be used to ask for help.

"Would you help me" is a polite way of asking "help me."

"Can you help me" means "Are you able to help me" and is used to ask for help, but is less formal.

"Will you help me" is a polite way of asking for help.

"Might you help me" is an uncommon, but polite, way of asking for help.

"Could you help me" means "Would you be able to help me" and is a polite way to ask for help.

You can also add a 'not' to some of these. The following all mean "help me." There is a difference in connotation with these negated forms, though.

Will you not help me?
Would you not help me?
Might you not help me?
Can you not help me?
Could you not help me?