modals

Modals are a class of auxiliary verbs used to express modality, the speaker’s attitude toward the action of the main verb. They convey meanings such as possibility, ability, permission, obligation, necessity, probability, and intention. In many languages, modals form a distinct subcategory of auxiliary verbs and interact with the main verb to create nuanced shades of meaning.

In English and other languages, modals combine with the base form of the main verb and typically do not take the usual inflections seen with main verbs. They do not add -s for third person singular, and they require do-support for questions and negation in English. For example: can go, must not go, will arrive. Some modals also express aspect or tense indirectly, often through periphrastic constructions such as have to, should have, or must have.

Common modals include can and could (ability or possibility), may and might (permission or probability), shall and should (offers, suggestions, or obligation), and will and would (future intention or hypothetical scenarios). Must conveys a strong sense of necessity or obligation. There is also ought to, a semi-modal, and periphrastic forms like have to or need to that function similarly in expressing obligation or necessity.

Modals are typically categorized into deontic modals, which express permission and obligation, and epistemic modals, which express probability or deduction about a proposition. Cross-linguistically, modal meanings may be encoded with auxiliary verbs, inflection, or periphrastic constructions, reflecting a common human concern with likelihood, capability, and authority in communication.