modal auxiliary: meaning, definition, pronunciation and examples
C1-C2Technical/Academic/Linguistics
Quick answer
What does “modal auxiliary” mean?
A class of auxiliary verbs that express modality — concepts like ability, permission, obligation, likelihood, and volition — rather than action.
Audio
Pronunciation
Definition
Meaning and Definition
A class of auxiliary verbs that express modality — concepts like ability, permission, obligation, likelihood, and volition — rather than action.
A grammatical term for verbs like can, could, may, might, shall, should, will, would, must, that modify the main verb to indicate the speaker's attitude toward the action or state. They lack certain verb forms (e.g., no -s, -ing, or infinitive). In linguistics, the category is also referred to as "modal verbs".
Dialectal Variation
British vs American Usage
Differences
Use of 'shall' is more common and formal in UK English for future with 'I/we'. US English rarely uses 'shall' outside legal/formal contexts. 'Should' is sometimes used where US uses 'would' in polite expressions (e.g., BrE 'I should like to' vs AmE 'I would like to').
Connotations
Similar.
Frequency
The term 'modal verb' is slightly more common than 'modal auxiliary' in general teaching. The frequency of the term itself is similar between varieties.
Grammar
How to Use “modal auxiliary” in a Sentence
[Modal Aux] + [Base Form Verb] (e.g., 'You must go')[Modal Aux] + [not] + [Base Form Verb] (e.g., 'She cannot swim')Vocabulary
Collocations
Examples
Examples of “modal auxiliary” in a Sentence
verb
British English
- 'May' is a modal auxiliary expressing permission.
- 'Shall' functions as a modal auxiliary for formal futurity.
American English
- 'Must' is a modal auxiliary indicating necessity.
- 'Would' serves as a modal auxiliary for hypothetical situations.
adverb
British English
- None. The term is not used adverbially.
American English
- None. The term is not used adverbially.
adjective
British English
- The modal auxiliary system in English is closed-class.
- We studied the modal auxiliary verbs.
American English
- A modal auxiliary function is key to understanding mood.
- This sentence lacks a modal auxiliary element.
Usage
Meaning in Context
Business
Used in training materials on business writing to discuss polite requests and obligations (e.g., 'We should consider' vs 'We must act').
Academic
Frequent in linguistics, grammar, and language teaching literature as a core descriptive term.
Everyday
Rarely used; speakers use the modals themselves without naming the category.
Technical
Essential in syntactic theory, grammatical descriptions, and EFL/ESL pedagogy.
Watch out
Common Mistakes When Using “modal auxiliary”
- Adding '-s' in the third person (e.g., 'She mays go').
- Using the full infinitive 'to' after the modal (e.g., 'He can to swim').
- Creating a past participle form (e.g., 'have musted').
- Using two modal auxiliaries consecutively in standard English (e.g., 'He will can come').
FAQ
Frequently Asked Questions
It is a marginal or semi-modal. It behaves like a modal (expresses obligation) but is followed by 'to' + base verb, unlike core modals.
The core modals are nine: can, could, may, might, shall, should, will, would, must. Linguists often include 'ought to' as a marginal modal.
Some are historically past forms (could, might, should, would), but in modern usage they often express modality rather than past time. They lack a consistent past tense formation rule.
Yes, in cases of ellipsis where the main verb is understood from context (e.g., 'Can you swim?' 'Yes, I can.').
A class of auxiliary verbs that express modality — concepts like ability, permission, obligation, likelihood, and volition — rather than action.
Modal auxiliary is usually technical/academic/linguistics in register.
Modal auxiliary: in British English it is pronounced /ˌməʊdəl ɔːɡˈzɪləri/, and in American English it is pronounced /ˌmoʊdəl ɔːɡˈzɪləri/. Tap the audio buttons above to hear it.
Phrases
Idioms & Phrases
- “None (it is a technical term).”
Learning
Memory Aids
Mnemonic
MODAL AUXILIARY: MODify A Verb's Attitude & Likelihood. It's an Auxiliary helper.
Conceptual Metaphor
A LENS THROUGH WHICH TO VIEW THE VERB (modals colour the action with possibility, necessity, etc.).
Practice
Quiz
Which of the following is a defining characteristic of a modal auxiliary in Modern English?