Mood and modality: what is the difference?

You may have come across the terms mood and modality and wondered what is the difference between them.

Mood is a grammatical notion, whereas modality is a semantic notion relating to such concepts as 'possibility', 'necessity', 'permission', 'obligation', etc.

Traditionally, modality is said to be implemented grammatically through three moods namely indicative, imperative and subjunctive. These three moods are then implemented as verb inflections.

The indicative is used in sentences or clauses that are typically used to make factual statements, as in this example:

The sun is shining brightly today.

Here we have a present tense third person singular -s ending on the verb rise, and traditionally this is said to show indicative mood. For regular lexical verbs we also have a past tense inflection, namely -ed.

The imperative mood is described as the form of a verb that is normally used in directing or commanding people to do something:

Leave your coat in the hallway, please.

The subjunctive mood is traditionally seen as the form of a verb that it used to speak about hypothetical, desirable or necessary situations:

It's important that she be informed of the changes.

You will have noticed my use of the word traditionally in the observations above, and this is because recently grammarians have started to think of mood somewhat differently.

In an earlier post I discussed the subjunctive mood, and said that many grammarians would now argue that English doesn't have it, because the verbs that are used to form the English 'subjunctive' do not have any dedicated verbal inflections. Despite this the National Curriculum does mention the subjunctive in its Glossary, here.

If you think about it, the same is true for the imperative: there are no special verb endings for the imperative. English simply uses the plain (or base) form of the verb. For this reason it's better to say that English doesn't have an imperative mood, but to speak instead of imperative clauses. These are clauses that normally lack a Subject.

What about the indicative? Well, there's a case for saying that English does have an indicative mood. However, it's only reflected in the third person singular present tense -s ending on lexical verbs, and in the past tense -ed ending for regular lexical verbs. So really, there isn't much left by way of of an indicative mood either in English. Instead, grammarians now often prefer to speak of declarative clauses which usually make factual statements.

How does all this relate to modality? How is modality expressed, if not through verb forms?

English mainly uses modal verbs for this. These form a subset of the auxiliary verbs. The core modals are: will/would, can/could, may/might, shall/should, and must. These are always followed by a bare infinitive form of the verb. Here are some examples:

I will read you text message later.

We could meet at 6 p.m.

They may arrive a little bit early.

You should stop moaning.

However, modality can also be expressed by other kinds of words, such as:

• Modal nouns: decree, demand, necessity, requirement, request.

• Modal adjectives: advisable, crucial, imperative, likely, necessary, probable, possible.

• Modal adverbs: arguably, maybe, perhaps, probably, possibly, surely.

The opposition between mood and modality is similar to that between tense and time.