modal verbs

Hi,

I am teaching modal verbs to my class. I am having a problem using modal verbs of permission. The modal verbs "can" and "may" are used to show permission. My problem is "Can these two words be used interchangably?" Or are there specific rules governing each?

Eg: May I borrow your pen please?
Can I come in?
May I have a glass of water please?
Can I have a glass of water please?

Thank You,
Jumas

[Casiopea]

Originally Posted by Jumas

Hi,

I am teaching modal verbs to my class. I am having a problem using modal verbs of permission. The modal verbs "can" and "may" are used to show permission. My problem is "Can these two words be used interchangably?" Or are there specific rules governing each?

Eg: May I borrow your pen please?
Can I come in?
May I have a glass of water please?
Can I have a glass of water please?

Thank You,
Jumas

Hello,

Speakers tend to use 'can' and 'may' synonymously:

Can I come in? or May I come in?

But, the traditional use is as follows:

can = ability
may = polite request

Can I come in? Is it possible for me to enter? Is the door locked?
May I come in? May I have your permission to enter?

Also,

Pat: Can I borrow your pencil?
Sam: I dunno. Can you? Are you able to? (joke) :D

Cas :D