Modal (Auxiliary)

Glossary of Grammatical and Rhetorical Terms

modal verbs
The core modals in English. (sorendls/Getty Images)

In English grammar, a modal is a verb that combines with another verb to indicate mood or tense. A modal (also known as a modal auxiliary or modal verb) expresses necessity, uncertainty, ability, or permission.

Most linguists agree that there are 10 core or central modals in English: can, could, may, might, must, ought, shall, should, will, and would. Other verbs—including need, had better and invariant be—may also function as modals (or semi-modals).

Unlike other auxiliaries, modals have no -s, -ing, -en, or infinitive forms. (Because ought requires a to-infinitive complement, some linguists regard it as a marginal modal.)

Also see:


From the Latin, "measure"

Examples and Observations

  • "When I was younger I could remember anything, whether it happened or not."
    (Mark Twain)
  • "She thought, I must hurry before the robbers come."
    (Jean Stafford, "The Interior Castle," 1947)
  • "[G]overnment of the people, by the people, for the people, shall not perish from the earth."
    (Abraham Lincoln, The Gettysburg Address, 1863)
  • "There are many things that we would throw away if we were not afraid that others might pick them up."
    (Oscar Wilde, The Picture of Dorian Gray, 1890)
  • "Afterward, when the firing ended, they would blink and peek up. They would touch their bodies, feeling shame, then quickly hiding it. They would force themselves to stand. As if in slow motion, frame by frame, the world would take on the old logic--absolute silence, then the wind, then sunlight, then voices. It was the burden of being alive."
    (Tim O'Brien, "The Things They Carried." The Things They Carried. Houghton Mifflin Harcourt, 1990)
  • Characteristics of Modal Auxiliaries in English
    - "A modal auxiliary has the following characteristics:
    • Takes negation directly (can't, mustn't).
    • Takes inversion without DO (can I? must I?).
    • 'Code' (John can swim and so can Bill).
    • Emphasis (Ann COULD solve the problem).
    • No -s form for third-person singular (*cans, *musts).
    • No non-finite forms (*to can, *musting)
    • No co-occurrence (*may will)
    The first four of these are what Huddleston (1976: 333) calls the NICE properties (Negation, Inversion, Code, Emphasis) and they very clearly draw a dividing line between auxiliaries and main verbs, a line which would be far from clear if we tried to use semantic characteristics. The last three, which are specifically 'modal' criteria (see Palmer 1979: 9), are needed to exclude the auxiliaries BE, HAVE, and DO."
    (Jennifer Coates, The Semantics of the Modal Auxiliaries. Routledge, 1983)

    - "As early as Old English, a group of verbs signaling modal characteristics of action share morphosyntactic and semantic features which later result in the formation of the category of modal auxiliaries. . . .

    "The most important syntactic developments which distinguish [modals] from other verbs are the following: (1) they lost their non-finite forms and their ability to take non-verbal objects; (2) the preterite forms came to be used in the present, future or timeless contexts; (3) they did not develop the to- link with an infinitive (in the Southern standard); (4) they became more and more uncommon in contexts where they were not followed by an infinitive."
    (Richard M. Hogg, et al., The Cambridge History of the English Language: 1476-1776. Cambridge University Press, 1999)
  • Modals and the Subjunctive
    "Modals are also used where some languages would use the subjunctive mood. The Modern English subjunctive is very restricted and examples are given in (11a) and (12a). Alternatives using modals are provided in (11b) and (12b):
    (11a) They insisted that he go. (subjunctive mood)
    (11b) They insisted that he should go.
    (12a) I wish it were Friday. (subjunctive mood)
    (12b) I wish it would be Friday.
    Since subjunctives are not common in Modern English, I will not go into this more deeply."
    (Elly Van Gelderen, An Introduction to the Grammar of English, rev. ed. John Benjamins, 2010)
  • Double Modals
    "Speakers of other varieties of English, primarily in the southeastern United States, routinely produce sentences with two modals and find this double modal construction completely natural. Which modals they are varies from person to person and across subregions of the Southeast:
    We might could sing at the concert.
    I may should apply for a new job.
    Two modals verbs is the limit however."
    (Kristin Denham and Anne Lobeck, Linguistics for Everyone. Wadsworth, 2010)

Pronunciation: MODE-l

mla apa chicago
Your Citation
Nordquist, Richard. "Modal (Auxiliary)." ThoughtCo, May. 2, 2017, Nordquist, Richard. (2017, May 2). Modal (Auxiliary). Retrieved from Nordquist, Richard. "Modal (Auxiliary)." ThoughtCo. (accessed March 23, 2018).