Modal verbs - how do we use them and why? stream with this is Englishing .

Whats the difference between: "Can I borrow this?" and "Could I borrow this?" or, "May I help?" and "Can I help?" What about "Will you help me?" versus "Would you help me?" When is it appropriate to use "Shall I?", and when is it better to use "Let me"? These are the kinds of questions that I get all the time from my students. Let's break down the differences once and for all, shall we?