Modal Auxiliary Verbs

Modal auxiliary verbs, also known as helping verbs, follow a different set of rules from regular verbs, and people use them differently in different parts of the country. For example, people who live in the South often use something called a double modal in sentences such as We might could harvest the corn.

Neal Whitman, Writing for
5-minute read
Episode #435

might could double modal

Not long ago, a listener who likes my iOS game Grammar Pop asked us to record a podcast on modal auxiliary verbs, so here it is! We’ll start with the basics of modals, and then talk about one way of using modals that’s associated with Southern American English. 

What Are the Auxiliary Verbs?

If you’ve listened to this podcast for a while, you’ve probably heard me talk about auxiliary verbs, which also go by the less-fancy name of helping verbs. English has only a few helping verbs, and we can divide them into four groups.

One group consists of forms of be: am, are, is, was, were, be, being, and been.

Another consists of forms of have: have, has, had and having.

A third category of helping verbs is forms of do: do, does, and did. (In case you’re wondering why the forms doing and done aren’t in the list, you can consider those helping verbs, too, if you like. If helping verbs were a football team, though, doing and done would be the benchwarmers, who never actually get sent in to play. See episode 320 for more about the overall strangeness of the verb do

The fourth group, you may have guessed, consists of the modal auxiliaries, but before we talk about them, I should note that be, do, and have aren’t always helping verbs. In the sentence Squiggly is running a marathon, the verb is is a helping verb, but in the sentence Squiggly is Aardvark’s second-best friend, it’s a linking verb. (You can learn more about linking verbs in the old “good vs. well” episode.) In the sentence Aardvark doesn’t eat grits, and has never wanted to, the verbs doesn’t and has are helping verbs, but in the sentence Aardvark does crossword puzzles, and has an amazing collection of Rubik’s cubes, the verbs does and has are ordinary verbs (or in linguist-speak, lexical verbs). 

What Are the Modal Auxiliary Verbs?

Moving on to the modal auxiliaries, the most common ones are will, would, shall, should, can, could, may, might, and must. Modal auxiliary verbs are defective—yes, that’s the actual term, defective. It means they’re missing some forms. For example, they don’t have third-person singular present tense forms—or to put it more plainly, sentences like he cans, she mays, and it woulds are ungrammatical. They also don’t have infinitive forms, so even though it would make sense, a sentence such as They seem to should practice more is ungrammatical. 

Another way in which modal auxiliaries differ from lexical verbs is that their past tense forms usually don’t show past time. In fact, you might not have even realized that some modal verbs are actually past-tense forms. I didn’t, until I started taking an interest in grammar. Will, shall, can, and may are present-tense forms. The corresponding past-tense forms are would, should, could, and might. Must doesn’t have a separate past tense. Of all the modal past tenses, the only one that’s used very much to refer to past time is could, as in When I was in high school, I could bench-press 300 pounds

Modal Auxiliary Verb Can Show How Likely Something Is

Instead of showing past time, past-tense modals typically perform one of two other functions. One of these functions is called modal remoteness, which is a technical term for unlikelihood. This is what you get in conditional sentences such as “If I won the lottery, I could start a new business.” (See episode 313 for more on conditionals like these.)  Even outside conditional sentences, past-tense modals show this kind of remoteness. For example, telling someone “She would help you” suggests that you just need to give her the word, whereas “She will help you” means it’s as good as done. 

Modal Auxiliary Verb Can Show Politeness

In a more specific kind of modal remoteness, the past tense of modal auxiliaries can show politeness. If you’re a native English speaker, you may have a gut feeling that it’s more polite to ask someone, “Could you do me a favor?” than “Can you do me a favor?” It sounds a little less pushy. That’s because the past tense could presents the scenario of someone doing you a favor as less likely than the present tense can does. It shows that you’re not assuming the person is just naturally going to do you a favor, and in this way it conveys politeness.

Modal Auxiliary Verb Can Change to Match the Tense of Other Verbs

Aside from modal remoteness, the other function that modal past tenses perform is backshifting, or as it’s sometimes known, sequence of tenses. Suppose Squiggly says to Aardvark, “I may go skiing in November.” If Aardvark is talking to Fenster about Squiggly later on, he might say, “Squiggly said he might go skiing in November.” The modal verb may gets put into the past tense might,not to indicate past time or show modal remoteness, but just to match the past tense said. Lexical verbs can backshift, too. If Aardvark tells Squiggly, “You’re my second-best friend,” and Squiggly tells Fenster about it later, he might say, “Aardvark said I was his second-best friend,” using was just to match the past tense said.

There Are Other Modals Too 

In addition to may, might, can, could, will, would, shall, should, and must, there are a few fringe members of the family of modal auxiliaries. One of them is ought, which is different from the others because it’s the only modal verb that takes an infinitive. So you can say, “We must go,” or “We should go, but if you use ought, it’s “We ought to go.” Even further out on the fringe are some archaic uses of need and dare, as in Silly people need not apply, and How dare you speak to me that way? 

Sometimes People in the South Use Double Modals

Finally, let’s talk about that use of modals that, according to the Yale Grammatical Diversity Project, is associated with Southern American English, as well as a few other varieties. It’s called the double modal, or multiple modal, and appears in sentences such as We might could help you and You might should apologize to him. The problem isn’t that these sentences don’t make sense. Even if you wouldn’t say these sentences yourself, you can tell that they mean the same thing as “We might be able to help you,” and “Maybe you should apologize to him.” But in Standard English, even though other helping verbs can follow a modal, modals themselves can’t. 


About the Author

Neal Whitman, Writing for Grammar Girl

Neal Whitman PhD is an independent writer and consultant specializing in language and grammar and a member of the Reynoldsburg, Ohio, school board. You can search for him by name on Facebook, or find him on Twitter as @literalminded and on his blog at literalminded.wordpress.com.