Modal verb

A modal verb is a type of verb that is used to indicate modality – that is: likelihood, ability, permission, request, capacity, suggestions, order and obligation, and advice etc. They always take base form of verb with them. Examples include the English verbs can/could, may/might, must, will/would and shall/should. In English and other Germanic languages, modal verbs are often distinguished as a class based on certain grammatical properties.

Function

A modal auxiliary verb gives information about the function of the main verb that it governs. Modals have a wide variety of communicative functions, but these functions can generally be related to a scale ranging from possibility ("may") to necessity ("must"), in terms of one of the following types of modality:

• epistemic modality, concerned with the theoretical possibility of propositions being true or not true (including likelihood and certainty)
• deontic modality, concerned with possibility and necessity in terms of freedom to act (including permission and duty)
• dynamic modality, which may be distinguished from deontic modality in that, with dynamic modality, the conditioning factors are internal – the subject's own ability or willingness to act

The following sentences illustrate epistemic and deontic uses of the English modal verb must:

• epistemic: You must be starving. ("It is necessarily the case that you are starving.")
• deontic: You must leave now. ("You are required to leave now.")

An ambiguous case is You must speak Spanish. The primary meaning would be the deontic meaning ("You are required to speak Spanish.") but this may be intended epistemically ("It is surely the case that you speak Spanish.") Epistemic modals can be analyzed as raising verbs, while deontic modals can be analyzed as control verbs.

Epistemic usages of modals tend to develop from deontic usages. For example, the inferred certainty sense of English must developed after the strong obligation sense; the probabilistic sense of should developed after the weak obligation sense; and the possibility senses of may and can developed later than the permission or ability sense. Two typical sequences of evolution of modal meanings are:

• internal mental ability → internal ability → root possibility (internal or external ability) → permission and epistemic possibility
• obligation → probability

In Germanic languages

English

Main article: English modal verbs

The following table lists the modal auxiliary verbs of standard English and various senses in which they are used:

Modal auxiliary	Epistemic sense	Deontic sense	Dynamic sense
can	That can indeed hinder.	You can sing underwater.	She can really sing.
could	That could happen soon.	-	He could swim when he was young.
may	That may be a problem.	May I stay?	-
might	The weather might improve.	-	-
must	It must be hot outside.	Sam must go to school.	-
shall	-	You shall not pass.	-
should	That should be surprising.	You should stop that.	-
will	She will try to lie.	I will meet you later.	-
would	Nothing would accomplish that.	-	We would eat out on Sundays.

The verbs in this list all have the following characteristics:

1. They are auxiliary verbs, which means they allow subject-auxiliary inversion and can take the negation not,
2. They convey functional meaning,
3. They are defective insofar as they cannot be inflected, nor do they appear in non-finite form (i.e. not as infinitives, gerunds, or participles),
4. They are nevertheless always finite and thus appear as the root verb in their clause, and
5. They subcategorize for an infinitive, i.e. they take an infinitive as their complement

The verbs/expressions dare, ought to, had better, and need not behave like modal auxiliaries to a large extent, although they are not productive (in linguistics, the extent commonly or frequently used) in the role to the same extent as those listed here. Furthermore, there are numerous other verbs that can be viewed as modal verbs insofar as they clearly express modality in the same way that the verbs in this list do, e.g. appear, have to, seem etc. In the strict sense, though, these other verbs do not qualify as modal verbs in English because they do not allow subject-auxiliary inversion, nor do they allow negation with not. Verbs such as be able to and be about to allow subject-auxiliary inversion and do not require do support in negatives but these are rarely classified as modal verbs because they inflect and are a modal construction involving the verb to be which itself is not a modal verb. If, however, one defines modal verb entirely in terms of meaning contribution, then these other verbs would also be modals and so the list here would have to be greatly expanded.

Defectiveness

In English, modals form a very distinctive class of verbs. They are auxiliary verbs like be, do, and have, but unlike other such verbs, they are grammatically defective. For example, have → has vs. should → *shoulds and do → did vs. may → *mayed, etc. In clauses that contain two or more verbs, any modal that is present always appears leftmost in the verb catena (chain). Thus, modal verbs are always finite and, in terms of syntactic structure, the root of their containing clause. The following dependency grammar trees illustrate this point:

The verb catenae are in blue. The modal auxiliary in both trees is the root of the entire sentence. The verb that is immediately subordinate to the modal is always an infinitive. The fact that modal auxiliaries in English are necessarily finite means that within the minimal finite clause that contains them, they can never be subordinate to another verb, e.g.,

a. Sam may have done his homework. The modal auxiliary may is the root of the clause.

b. *Sam has may done his homework. Fails because the modal auxiliary may is not the root of the clause.

a. Jim will be helped. The modal auxiliary will is the root of the clause.

b. *Jim is will be helped. Fails because the modal auxiliary will is not the root of the clause.

Such limits in form (tense, etc.) and syntactic distribution of this class of verbs are motivation of the designation defective. Other constructions are frequently used for such a "missing" form in place of a modal, including "be able to" for can, "have to" for must, and "be going to" for shall and will (designating the future). It is of note that in this way, English modal auxiliaries are unlike modal verbs in other closely related languages; see below.

Do constructions

In English, main verbs but not modal verbs always require the auxiliary verb do to form negations and questions, and do can be used with main verbs to form emphatic affirmative statements. Neither negations nor questions in early modern English used to require do.

	normal verb	modal verb
affirmative	he works	he can work
negation	he does not work	he cannot work
emphatic	he does work hard	he can work hard
question	does he work here?	can he work at all?
negation + question	does he not work here?	can he not work at all?

(German, Afrikaans, and West Frisian never use "do" as an auxiliary verb for any function; Low Saxon and Dutch use "do" as an auxiliary, but only in colloquial speech in Dutch, whereas in Low Saxon it is of very common use, sometimes to a point where it is comparable to the way the English makes use of it).

Comparison with other Germanic languages

The English modal verbs share many features and often etymology with modal verbs in other Germanic languages.

The table below lists some modal verbs with common roots in the West Germanic languages English, German, Dutch, Low Saxon, West Frisian and Afrikaans, the North Germanic languages Danish, Swedish and Faroese, and the extinct East Germanic Gothic language. This list comprises cognates, which evolved from old Germanic modal auxiliaries. It does not attempt to be complete for any one of the modern languages, as some verbs have lost or gained modal character later in separate languages. (English modal auxiliary verb provides an exhaustive list of modal verbs in English, and German verb#Modal verbs provides a list for German, with translations. Dutch verbs#Irregular verbs gives conjugations for some Dutch modals.)

Words in the same row of the table below share the same etymological root. Because of semantic drift, however, words in the same row may no longer be proper translations of each other. For instance, the English and German verbs will are completely different in meaning, and the German one has nothing to do with constructing the future tense. These words are false friends.

In (modern) English, Afrikaans, Danish, and Swedish, the plural and singular forms are identical. For German, Dutch, Low Saxon, West Frisian, Faroese and Gothic, both a (not the) plural and a singular form of the verb are shown. Forms within parentheses are obsolete, rare, and/or mainly dialectal in the modern languages.

Etymological relatives (not translations)

English	German	Dutch	Low Saxon	West Frisian	Afrikaans	Danish	Swedish	Faroese	Gothic
can	können, kann	kunnen, kan	könen, kann	kinne, kin	kan	kan	kan	kunna, kann	kunnum, kann
shall	sollen, soll	zullen, zal	schölen, schall	sille, sil	sal	skal	ska(ll)	skula, skal	skulum, skal
will	wollen, will	willen, wil	wüllen, will	wolle, wol	wil	vil	vill	vilja, vil	wileima, wiljau
(mote), must	müssen, muss	moeten, moet	möten, mutt	moatte, moat	moet	måste	måste	?	-,gamōt
may	mögen, mag	mogen, mag	mögen, mag	meie, mei	mag	må	(må)	mega, má	magum, mag
(wit)	wissen, weiß	weten, weet	?	?	weet	ved	vet	vita, veit	witum, wait
(tharf)	dürfen, darf	durven, durf	dörven, dörv	doarre, doar	durf	?	(torv)	?	þaúrbum, þarf

The English could is the preterite form of can; should is the preterite of shall; might is the preterite of may; and must was originally the preterite form of mote. (This is ignoring the use of "may" as a vestige of the subjunctive mood in English.) These verbs have acquired an independent, present tense meaning. The German verb möchten is sometimes taught as a vocabulary word and included in the list of modal verbs, but it is actually the past subjunctive form of mögen.

The English verbs dare and need have both a modal use (he dare not do it), and a non-modal use (he doesn't dare to do it). The Dutch, West Frisian, and Afrikaans verbs durven, doarre, and durf are not considered modals (but they are there, nevertheless) because their modal use has disappeared, but they have a non-modal use analogous with the English dare. Some English modals consist of more than one word, such as "had better" and "would rather".

Owing to their modal characteristics, modal verbs are among a very select group of verbs in Afrikaans that have a preterite form. Most verbs in Afrikaans only have a present and a perfect form.

Some other English verbs express modality although they are not modal verbs because they are not auxiliaries, including want, wish, hope, and like. All of these differ from the modals in English (with the disputed exception of ought (to)) in that the associated main verb takes its long infinitive form with the particle to rather than its short form without to, and in that they are fully conjugated.

Morphology and syntax

Germanic modal verbs are preterite-present verbs, which means that their present tense has the form of a vocalic preterite. This is the source of the vowel alternation between singular and plural in German, Dutch and Low Saxon. Because of their preterite origins, modal verbs also lack the suffix (-s in modern English, -t in German, Dutch, Low Saxon and West Frisian, -r in the North Germanic languages, -þ in Gothic) that would normally mark the third person singular form. Afrikaans verbs do not conjugate, and thus Afrikaans non-modal verbs do not have a suffix either:

	normal verb	modal verb
English	he works	he can
German	er arbeitet	er kann
Dutch	hij werkt	hij kan
Low Saxon	he warkt	he kann
West Frisian	hy wurket	hy kin
Afrikaans	hy werk	hy kan
Danish	han arbejder	han kan
Swedish	han arbetar	han kan
Faroese	hann arbeiðir	hann kann
Gothic	?	is kann

The main verb that is modified by the modal verb is in the infinitive form and is not preceded by the word to (German: zu, Low Saxon to, Dutch and West Frisian te, Afrikaans om te,). There are verbs that may seem somewhat similar in meaning to modal verbs (e.g. like, want), but the construction with such verbs would be different:

	normal verb	modal verb
English	he tries to work	he can work
German	er versucht zu arbeiten	er kann arbeiten
Dutch	hij probeert te werken	hij kan werken
Low Saxon	he versöcht to warken	he kann warken
West Frisian	hy besiket te wurkje	hy kin wurkje
Afrikaans	hy probeer om te werk	hy kan werk

Similarly, in North Germanic languages, the infinitive marker (at in Danish and Faroese, att in Swedish) is not used for main verbs with modal auxiliaries: Han kan arbejde, han kan arbeta, hann kann arbeiða (he can work). However, there also are some other constructions where the infinitive marker need not be employed, as in Swedish han försöker arbeta (he tries to work).

Less defective

In many Germanic languages, the modal verbs may be used in more functions than in English. In German, for instance, modals can occur as non-finite verbs, which means they can be subordinate to other verbs in verb catenae; they need not appear as the clause root. In Swedish, some (but not all) modal verbs have infinitive forms. This for instance enables catenae containing several modal auxiliaries. The modal verbs are underlined in the following table.

Language	Sentence
English	he must be able to do it
German	er muss das tun können
Swedish	han måste kunna göra det

(The Swedish sentence translated word by word would yield the impossible "*he must can do it"; the same goes for the German one, except that German has a different word order in such clauses, yielding "*he must it do can".)

(In general, there is no correspondence to the "do" constructions in other germanic languages; whence there is no question of how it is used with the modals. German, Afrikaans, and West Frisian never use "do" as an auxiliary verb for any function; Low Saxon and Dutch use "do" as an auxiliary. In Low Saxon it is of very common use, sometimes to a point where it is comparable to the way the English makes use of it).

In English, modal verbs are called defective verbs because of their incomplete conjugation: they have a narrower range of functions than ordinary verbs. For example, most have no infinitive or gerund.

In other languages

Hawaiian Creole English

Hawaiian Creole English is a creole language most of whose vocabulary, but not grammar, is drawn from English. As is generally the case with creole languages, it is an isolating language and modality is typically indicated by the use of invariant pre-verbal auxiliaries. The invariance of the modal auxiliaries to person, number, and tense makes them analogous to modal auxiliaries in English. However, as in most creoles the main verbs are also invariant; the auxiliaries are distinguished by their use in combination with (followed by) a main verb.

There are various preverbal modal auxiliaries: kaen "can", laik "want to", gata "have got to", haeftu "have to", baeta "had better", sapostu "am/is/are supposed to". Unlike in Germanic languages, tense markers are used, albeit infrequently, before modals: gon kaen kam "is going to be able to come". Waz "was" can indicate past tense before the future/volitional marker gon and the modal sapostu: Ai waz gon lift weits "I was gonna lift weights"; Ai waz sapostu go "I was supposed to go".

Hawaiian

Hawaiian, like the Polynesian languages generally, is an isolating language, so its verbal grammar exclusively relies on unconjugated verbs. Thus, as with creoles, there is no real distinction between modal auxiliaries and lexically modal main verbs that are followed by another main verb. Hawaiian has an imperative indicated by e + verb (or in the negative by mai + verb). Some examples of the treatment of modality are as follows: Pono conveys obligation/necessity as in He pono i na kamali'i a pau e maka'ala, "It's right for children all to beware", "All children should/must beware"; ability is conveyed by hiki as in Ua hiki i keia kamali'i ke heluhelu "Has enabled to this child to read", "This child can read".

French

French, like some other Romance languages, does not have a grammatically distinct class of modal auxiliary verbs; instead, it expresses modality using conjugated verbs followed by infinitives: for example, pouvoir "to be able" (Je peux aller, "I can go"), devoir "to have an obligation" (Je dois aller, "I must go"), and vouloir "to want" (Je veux aller "I want to go").

Italian

Like in other Romance languages, modal verbs in Italian (verbi modali or verbi servili) together with the preterite (passato remoto) possess the perfect form (passato prossimo), where they have the peculiarity to preferably inherit the auxiliary verb from the verb they hold. Although when used alone, the auxiliary of modal verbs is always avere ("have"). Italian can use both avere ("have") and essere ("be") as auxiliaries. Modal verbs in Italian are the only group of verbs allowed to follow this particular behavior, forming so a distinct class.

For example, the perfect of potere ("can") is avere ("have"), as in ho potuto ("I could"); nevertheless, when used together with a verb that has as auxiliary essere ("be"), potere inherits the auxiliary of the second verb.

E.g.: ho visitato il castello ("I have visited the castle") / ho potuto visitare il castello ("I could visit the castle") – but: sono scappato ("I have escaped") / sono potuto scappare ("I could escape").

Italian modal verbs that follow this particular pattern are: potere ("can"), volere ("want"), dovere ("must"), sapere ("to be able to").

Mandarin Chinese

Mandarin Chinese is an isolating language without inflections. As in English, modality can be indicated either lexically, with main verbs such as yào "want" followed by another main verb, or with auxiliary verbs. In Mandarin the auxiliary verbs have six properties that distinguish them from main verbs:

• They must co-occur with a verb (or an understood verb).
• They cannot be accompanied by aspect markers.
• They cannot be modified by intensifiers such as "very".
• They cannot be nominalized (used in phrases meaning, for example, "one who can")
• They cannot occur before the subject.
• They cannot take a direct object.

The complete list of modal auxiliary verbs consists of

• three meaning "should",
• four meaning "be able to",
• two meaning "have permission to",
• one meaning "dare",
• one meaning "be willing to",
• four meaning "must" or "ought to", and
• one meaning "will" or "know how to".

Spanish

Spanish, like French, uses fully conjugated verbs followed by infinitives. For example, poder "to be able" (Puedo andar, "I can walk"), deber "to have an obligation" (Debo andar, "I should walk"), and querer "to want" (Quiero andar "I want to walk").

The correct use of andar in these examples would be reflexive. "Puedo andar" means "I can walk", "Puedo irme" means "I can go" or "I can take myself off/away". The same applies to the other examples.

See also

• English auxiliaries and contractions
• German modal particle
• Grammatical mood
• Modal logic

Bibliography

• The Syntactic Evolution of Modal Verbs in the History of English
• Walter W. Skeat, The Concise Dictionary of English Etymology (1993), Wordsworth Editions Ltd.

{Expand section|date=May 2008}

External links

• German Modal Verbs A grammar lesson covering the German modal verbs
• (in Portuguese) Modal Verbs
• Modal Verb Tutorial