QUESTION: How does may change in reported speech?
ANSWER: As a colleague of mine said, I opened the proverbial can of worms by taking on reported speech recently on my YouTube channel. The number of rules concerning changes to verbs is especially high, and some of the rules I dared to challenge.
If grammar sources address modal verbs in reported speech, the list of changes is often limited to a half dozen or so. One modal that is often included is may, but the only rule stated is that may changes to might. Is it as simple as that?
Example 1a:
“The meeting may end early,” Pete said.
Pete said that the meeting might end early.
This makes sense, though I’d note that the general rules for verb tense changes still apply. If we are immediately reporting Pete’s words, then it’s not really necessary to change may.
Example 2a:
“No one may leave the meeting before the vote is taken,” said the director.
The director said that no one __?__ leave the meeting before the vote was taken.
Is it necessary and logical to change may to might in this reported statement? Wouldn’t it sound more natural to use could? I’d argue yes. For statements expressing permission (or lack of it, i.e., prohibition), may changes to could:
The director said that no one could leave the meeting before the vote was taken.
And here’s an example with the negative:
Example 2b:
“You may not abstain from voting,” the director said.
The director said that we couldn’t abstain from voting.
Does that mean may changes to could only when we’re expressing permission? No. Let’s go back to Example 1 and test out could:
Example 1b:
“The meeting may end early,” Pete said.
Pete said that the meeting could end early.
Isn’t could an acceptable alternative that expresses the possibility of the meeting ending early? If so, then let’s see what happens in negative statements that express possibility:
Example 3:
“You may not make the 5:15 train home,” Sally said.
Sally said that I __?__ not make the 5:15 train home.
I think only might is possible in this statement. Could no longer expresses the unlikelihood that may did in the original statement. The reported statement must be:
Sally said that I might not make the 5:15 train home.
Summary
Quoted speech > reported speech
MAY > might – or – could = to express possibility
MAY NOT > might not = to express unlikelihood
MAY > could = to express permission
MAY NOT > could not = to express prohibition
English with Jennifer 
Hi! Thanks for the really interesting article! Could you please give one more example where may not express unlikelihood? I did not understand it well.
Thanks in advance:)
Hello Anastasia,
If we’re not using reported speech, but simply making a direct statement, then we can offer these examples to our students:
1. You may not make the 5:15 train because it’s already 5:00 and there’s a lot of traffic. = It’s likely you won’t make it.
2. We may not have time to stop at the store on our way to the movies because we’re running late. = It’s likely we won’t stop at the store.
3. Emma may not be home yet. She likes to exercise after work and then head home. = It’s unlikely that Emma is home this early.
I hope that helps. Regards!