Carol in Texas asks:
We attended a baseball game recently where helpers were spaced around the stadium with signs stating “How Can I Help You?”
Isn’t the actual correct usage “How May I Help You?”
This question has really been bothering my entire family, and we are split down the middle of which is right or wrong, may vs can.
The distinction between the two is often blurred. But "can" refers to actual ability to do something:
He can play the piano.
They can't score a goal even when they try.
We can get there by noon if we leave now.
"May" involves choice and sometimes uncertainty:
You may leave the room when you finish the test.
If the traffic is good, we may get there by noon.
They may score a goal if they get a lucky break.
Suppose some bashful guy approaches a lovely girl and asks: "Can I take you to the dance?" Well, no doubt he can, if he's got access to a car or cab fare. Instead he should ask: "May I take you to the dance?" In other words, will you choose to go to the dance with me?
So in the case you mention, the signs should say: "How May I Help You?" Presumably the helpers can help you—that is, they have the training and ability. But until you tell them what you need, they're uncertain; it's up to you to choose.