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Real Grammar Quiz, Question 9: should I say “Can I…” or “May I …”?

Macmillan Dictionary – Real GrammarReal Grammar isn’t about the made-up or outdated “rules” which some people try to make us follow. As we said in the introduction to this new series from Macmillan DictionaryReal Grammar is based on the evidence of language in use.

In this series, we’ll be bringing you blog posts and videos that give evidence-based answers to frequently asked questions about grammar and usage. There’s also a Real Grammar quiz for you to try.


In the ninth question in our Real Grammar quiz, we asked which of these sentences was acceptable:

May I bring my sister too?
Can I bring my sister too?

There is a traditional rule that you should use “may” when asking for (or giving) permission to do something, while “can” is reserved for talking about someone’s ability or capacity to do something – as in Can you play the guitar? This is what I learned at school, and I dare say many of our readers were taught this “rule” too.

The evidence of usage tells a different story. Corpus data shows that may – when used for asking permission – has been declining for several decades, and in present-day discourse can is over ten times as common in this use. Even the usually conservative American Heritage Usage Panel is beginning to accept this development. Back in the 1990s, over 50% of its members disapproved of the sentence Can I take another week to submit the application? But by 2009, this had fallen to 37%, and most of them felt it was was only “somewhat (rather than completely) unacceptable”.

But the old rule is not merely out of date. The real problem is that it oversimplifies the complex patterns of use of these two modal verbs. Both can and may – as their entries in the Macmillan Dictionary demonstrate – have several distinct uses. People often use Can I… to  inquire about what is permissible according to the rules:

Can I travel outside the U.S. during my training program?
Can I borrow books or articles from other libraries?

It is also used for talking about what is technically possible, and this usage often turns up in FAQs like this:

Q: Can I run client/server applications like PeopleSoft Human Resources package?
A: Yes, we support all client/server applications ….

As for May I at the start of a sentence, its commonest use is as a rhetorical device – typically in a speech or official meeting – for introducing a statement or suggestion (rather than a question):

May I say how deeply honoured I am to be invited to chair the NCVO.
May I suggest that your readers lobby their MPs on this subject.
May I extend my heartiest congratulations to the whole team on publishing their 200th issue.

With regard to asking or giving permission, the problem with the traditional rule is that it fails to take any account of register: the social context in which an utterance occurs, and the level of formality appropriate to it. Because although may is no longer common in this use, it has its place in the language, and is perfectly acceptable in official or formal contexts. It is often used, for example, when explaining what is permitted according to laws or regulations:

Council members may claim expenses for all reasonable costs in their roles as Council member.
Overseas candidates may submit a portfolio or samples of their project work in a digital format.

But in our quiz, the context was a conversation between friends, and in an informal situation like this, saying “May I bring my sister?” would sound pompous and not at all appropriate. In a recent Life Skills post on asking and giving permission, we showed that there is a range of options available, such as the more indirect could (Could I borrow your bike for a couple of hours?), and expressions like Do you mind if I open the window? or Would it be all right if we parked in your driveway?  As pointed out there, can is the simplest and most common choice, while may is “a more formal and polite way of asking permission”.

To read more about Real Grammar, keep a close eye on our Real Grammar page. You can catch up with the videos on our YouTube channel, where the tenth video in the series is now live. You can also follow this topic using #realgrammar on Twitter and remember that you can find all our earlier blog posts on this topic by using the tags “prescriptivism” or “realgrammar”.

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Michael Rundell


  • A look at the Google N-Gram Viewer shows an interesting history. From the mid-1940 through1960, there was a sudden rise and sustained usage of “May I” Then it started dropping pretty sharply until a rapid rise about 15 years ago.. In the mid-1970s, “Can I” started a mercurial rise.that seems to be continuing..

  • There is a traditional rule that you should use “may” when asking for (or giving) permission to do something, while “can” is reserved for talking about someone’s ability or capacity to do something – as in Can you play the guitar? This is what I learned at school, and I dare say many of our readers were taught this “rule” too.”
    The reason for not allowing these two distinctive words to be devalued by frequent incorrect usage is beautifully encapsulated in the paragraph above. The two very different meanings are absolutely crystal clear. They are unmistakable. The logic and purpose is impeccable and faultless. While some ‘rules’ might be considered arbitrary, this one is so manifestly useful that it SHOULD be written in stone. Abandoning it to mob rule would be unforgivable. There is inarguably good reason to maintain this rule and absolutely nothing to justify its abandonment.

  • Sir, greetings of the day. ‘Can I post my comment, please?’
    ‘Yes, you can, provided you are thorough in the subject’.
    ‘May I post my comment,please?’
    ‘Of course, this space is meant for doing so’.
    I think this is how it goes. But the mob rule has become the (dis)order of the day in using the language. Words like ‘anyway’ being used in the plural (anyways!) or pronouncing ‘write’ as ‘vrite’, have become very common; but it is very hard to see the language getting degraded. Just to give the English language a casual tone, this ‘death’ of syntax, pronunciation, distortion,etc is condemnable, and needs a censure outright. Let’s preserve the order of English language.
    Thank you.

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