Non-Modal Expressions of Modality
Modality isn't just about modal verbs like can, must, or should. English also expresses possibility, necessity, and likelihood through adverbs, adjectives, and nouns. These non-modal tools let you fine-tune how certain, how urgent, or how obligatory something sounds, often with more precision than a modal verb alone.
Three Categories of Non-Modal Modality
Each word class contributes to modality in a different way:
- Adverbs modify verbs, adjectives, or other adverbs to express degrees of certainty or likelihood (possibly, probably, certainly)
- Adjectives describe nouns or pronouns to convey necessity, importance, or possibility (necessary, essential, likely)
- Nouns name modal concepts directly and combine with verbs or prepositions to build modal meaning (possibility, obligation, permission)
The sections below break down each category with examples.
Adverbs for Degrees of Likelihood
Modal adverbs sit on a spectrum from low certainty to high certainty. Choosing the right one changes how confident your statement sounds.
- Possibly signals low certainty: "She might possibly attend the event."
- Probably expresses higher likelihood: "He will probably finish the project on time."
- Certainly conveys strong confidence: "They will certainly win the competition."
Other common modal adverbs include maybe, perhaps, likely, undoubtedly, and definitely. Notice that many of these can work alongside modal verbs ("She might possibly come"), which layers two kinds of modality together.
Adjectives for Importance or Necessity
Modal adjectives often appear in "It is + adjective + to..." constructions, where they express how required or important something is.
- Necessary indicates a requirement: "It is necessary to study for the exam."
- Essential emphasizes fundamental importance: "Regular exercise is essential for good health."
- Crucial stresses that something is critical: "Teamwork is crucial for the project's success."
Other modal adjectives include important, vital, imperative, optional, possible, and likely. Pay attention to the range here: imperative sounds much stronger than important, and optional actually weakens obligation rather than strengthening it.
Nouns for Modal Concepts
Modal nouns name the concept of modality itself. They typically combine with verbs like have, give, or exist, or with prepositions like of and for.
- Possibility pairs with verbs or prepositions: "There is a possibility of rain" or "The possibility for success exists."
- Obligation combines with verbs or prepositions: "We have an obligation to help" or "The obligation of citizenship includes voting."
- Permission appears in phrases with give, grant, or receive: "She gave permission to proceed" or "Permission for construction was granted."
Other modal nouns include probability, likelihood, necessity, requirement, and chance. These tend to sound more formal than their modal verb equivalents. Compare "You must help" with "We have an obligation to help": same core meaning, but the noun version feels weightier and more official.