Modality

Modality refers to the speaker's attitude or perspective toward the content of the main clause, or toward the state of affairs expressed by the main verb and predicate. In other words, it refers to the speaker's beliefs about the sentence predicate, or how it should be interpreted by the listener. Very simply put, modality is a meta-statement about the main predicate. E.g.:

1. The show must go on. (Queen)
2. I would do anything for love. (Meatloaf)
3. I can't stand losing you. (Sting)

In these sentences, the verbs must, would, can't indicate the speakers' assessments of the situation, their truth conditionality, their potential, or likelihood. Modality is realized in different ways in different languages.

1. Verb forms. If the main verb is conjugated to reflect modality, it is often called grammatical mood or mode. Common examples are Latin, Spanish, and French, with their distinctions between indicative (declarative, factual) and subjunctive moods.
2. Verbal auxiliaries, e.g., English modal verbs.
3. Separate main verbs, e.g., want, seem.

The most common modalities in English and other languages are as follows. Some of these may overlap.

1 Indicative

This is the default interpretation of basic verbs when not modified by special mood morphemes or modals. This treats a statement as factual or certain, or (in the future) as likely factual or certain to happen. E.g.:

• My hovercraft is full of eels. (Monty Python)
• You're the reason our kids are ugly. (Loretta Lynn & Conway Twitty)
• I will follow. (U2)

These are understood as statements of fact or certainly. It can also overlap with or be similar to what is called declarative modality, as in so-called declarative questions.

2 Realis

Realis means that something is stated as factual, and has actually happened. It thus overlaps with indicative and declarative modalities. In English and other languages, it is usually expressed with present and past indicative tenses.

• It's the end of the world as we know it. (REM)
• I still haven't found what I'm looking for. (U2)
• The piano has been drinking. (John Waite)

3 Irrealis

Irrealis refers to states or events that have not happened, or have not happened yet. This includes counter-factual (contrafactual) statements, conditional statements, future tenses, and commands (imperatives). English has the following types in its grammar: imperative, jussive, subjunctive, and conditional; it can express others (optative, inferential) by other means.

3.1 Imperative

Commands refer to actions that have not yet happened.

• Have yourself a merry little Christmas. (Judy Garland; Frank Sinatra)
• Don't do me like that. (Tom Petty)
• Don't stop believing. (Journey)
• Let it be. (Beatles)

3.2 Conditional

Conditional statements include if-statements as well as statements of what is potential, hypothetical, or advisable. It is generally expressed with conditional modal verbs (could, would, should, might, may).

• If I could read your mind, love, what a tale your thoughts could tell. (Gordon Lightfoot)
• I'd rather have a bottle in front of me, than a frontal lobotomy. (Randy Hanzlick, Dr. Demento collection)

3.3 Subjunctive

Subjunctive refers to various types of conditional and counter-factual predicates. This was once a commonly used verb paradigm in English to express these concepts, but it has largely been replaced by conditional modal verb forms. It survives in a few fossilized forms in current English grammar, while it is common in other European languages like Spanish, French and German. In addition to standard conditionals and counter-factuals, it was used for third-person commands or wishes, and one area where this is still used is in stage directions in plays (Enter Romeo = Have/let Romeo enter); hence its use in this song title:

• Enter Sandman. (Metallica)

3.4 Jussive

Suggestions or requests in first-person, to a group of people, including a speaker. In other words, let's __ expressions.

• Let's dance. (David Bowie)
• I've got the brains. You've got the looks. Let's make lots of money. (Pet Shop Boys)

3.5 Others

These do not have unique grammatical or lexical forms in English, so they are expressed with other verb forms, or occasionally, adverbially. They can have separate forms in other languages.

1. Optative. This refers to wishes, and is expressed in English with conditional verbs (e.g., If only I were wiser or If only I had listened). Classical Greek used separate verb forms for this; other European languages might use subjunctive verbs.
2. Potential. This refers to (unrealized) possibility, and is expressed in English with adverbs, epistemic modals or conditional verbs (e.g., I might possibly go).
3. Inferential. This means the speaker has inferred something, and is expressed in English with epistemic modals (e.g., You must be mad).

4 Modal Verbs: Deontic & Epistemic

English modal verbs primarily express two modalities in addition to conditional and counter-factual modalities: epistemic and deontic. Epistemic refers to whether how true or knowable something might be - in other words, potential. Deontic refers to necessity or obligation.

4.1 Epistemic

Epistemic is primarily represented by can, could, may, might for possibility or potential. The modals can, could tend to focus on internal ability, e.g., The President could be lying is a statement based on what the speaker thinks of the person's nature, character, ability, past history, or other factors internal to the subject (e.g., he's done this before, or he's a liar or an idiot). On the other hand, may and might focus more on the external, such as the speaker's assessment of the situation; thus, a statement like The President may/might be lying are based on what the speaker sees as a suspicious situation or circumstances (e.g., accusations of an affair from another woman, or no enemy weapons of mass destruction to justify a war). This type of distinction in European languages like English may be unfamiliar to students from, e.g., East Asian countries, whose first languages lack this internal/external distinction.

• Nobody can do the shing-a-ling like I do (Human Beinz)
• Can you read my mind? (The Killers)
• We could be heroes. (David Bowie)
• I can see for miles. (The Who)

While must is primarily deontic, it can take on a secondary meaning as an epistemic modal, conveying strong, inferred probability (e.g., The President must be lying).

• This must be the place I waited years to leave. (Pet Shop Boys)

4.2 Deontic

Modals expressing need, necessity, or obligation are deontic, such as must, need to, have to. The necessity or sense of obligation could be more internal, e.g., what the speaker herself/himself feels is needed (more often expressed with need to or have to), or it could be more external, i.e., the speaker views it as a social obligation or a necessity due to external circumstances (more often with must, should).

• The show must go on. (Queen)
• Should I stay or should I go? (The Clash)

In formal English, may can be deontic (May I go? - Yes, you may go.). In requests for permission, the modals can, could colloquially take on a deontic meaning, e.g., Could I go? or Can I go? are more colloquial for the formal May I go?.

• If you leave me, can I come too? (Mental As Anything)

5 Interrogative cf. Declarative

Interrogative is simply a question form, assuming something to be possible but unknown to the speaker, and declaratives are simply statements of fact or potential fact.

• Does your chewing gum lose its flavor on the bedpost overnight? (interrogative) (Lonnie Donegan, novelty hit from Dr. Demento collection)
• Does anybody really know what time it is? (interrogative) (Chicago)
• Are 'friends' electric? (interrogative) (Gary Numan)
• Where are we now? (David Bowie)
• Yes, we have no bananas. (declarative) (Frank Silver / Irving Cohn)
• The devil went down to Georgia. (declarative) (Charlie Daniels Band)

6 Evidential cf. Inferential

Some non-Western languages express evidentiality, that is, whether the speaker knows the information first-hand, has heard it from someone else, or has inferred it. The first two represent different degrees of evidentiality, and the latter, by inference, is inferential, which may be treated as a type of irrealis. Altogether, the phenomenon of, and forms for, expressing levels of evidential and inferential modality is called evidential and evidentiality. These are expressed with verbal endings or special discourse markers.