Modality: meanings and uses

Modal meaning

We often use modal verbs or other modal expressions when we want to express an opinion or attitude about a possible fact or to control a possible action. All modal expressions are about the speaker’s or writer’s view of the world.

Compare

He’s her brother. She told me.	I know this fact for certain. I am not expressing an opinion about it. I am stating it as a fact.
He must be her brother. They look so much alike.	I am expressing an opinion about a fact because of the evidence that I have.

Jan always goes with us.	I’m not expressing an attitude or opinion about this action.
OK. Jan can go if she’s finished.	I’m controlling a possible action. I’m giving Jan permission.

We can divide most modal words and expressions into two types of meaning:

The speaker or writer decides how certain something is, either in the present, future or past. They predict or speculate about a fact. We see this type of meaning when we talk about degrees of certainty, possibility, likelihood, doubt:

Paula can’t be home yet. It’s impossible. She left 10 minutes after us.

[The speaker hears the phone ring and predicts who is ringing.]

There’s the phone. That’ll be Mum.

I may go. I haven’t decided yet.

The speaker or writer wants to control or ‘direct’ the action. They give and refuse permission. They talk about obligation and necessity. They talk about how they would like the world to be:

[parent says to child]

You can come if you’re good.

He should take more care.

Tell Jen she needn’t bother about the washing up.

You mustn’t worry so much about her.

You may go now. (formal)

Modal verbs

Often the same modal verb is used to express different meanings.

meaning	which verb?	example
really certain	will	My birthday will be on a Monday this year.
	won’t	I won’t have a party.
	shall	I shall have plenty to tell you when I see you.
	shan’t	I shan’t ask you to come again.
	must	The cakes must be ready soon. They’ve been in the oven for an hour.
	can’t	You can’t be hungry. You had a huge lunch.
very likely	should	The traffic isn’t heavy. We should be there in an hour.
very likely	ought to	The traffic isn’t heavy. We ought to be there in an hour.
possible	may	She may be a friend of Richard’s.
	might	She might be a friend of Richard’s.
	could	She could be a friend of Richard’s.
strong obligation	must	You must arrive at 6 to pick up the tickets.
	have to	I have to go up to the hospital twice a week.
	need to	We need to win this game to get into the final.
weak obligation	should	Children should look after their parents in old age.
weak obligation	ought to	Children ought to look after their parents in old age.
no obligation	needn’t	I needn’t do it now. I’ll do it later.
	don’t need to	I don’t need to do it now. I’ll do it later.
	don’t have to	I don’t have to do it now. I’ll do it later.
permission	can	Can we go out now? You can go now if you’ve finished.
	may	You may go now if you’ve finished. May I borrow a chair?
	could	Could we borrow the car?
	might	Might we have a little more time to finish the exam? (very formal)
no permission	can’t	You can’t go in without a ticket.
	may not	You may not enter while the exam is in progress. (formal)
	must not	You must not leave your bike in front of the fire exit.
offer	will	I’ll get it. You stay there.
offer	shall	Shall I go and make dinner?
request	will	Will you close that door?
	would	Would you close that door?
	could	Could you help me with this?
promise	will	I’ll come back before 6.
decision	will	I think I’ll eat later. I’m not hungry now.
advice and suggestion	should	You should apply for that job.
ability	can	Can you swim underwater?
ability	could	I could play much better ten years ago.
general truth	can	Too much exercise can be bad for you.
general truth	may	A list of verbs may be found at the back of the book.