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, obligation, or advice. Modal verbs always accompany the base form of another verb having semantic content. In English, the modal verbs commonly used are can, could, may, might, must, will, would, shall, should, ought to, had better, have to and sometimes need or dare. 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 to necessity, in terms of one of the following types of modality:
The following sentences illustrate epistemic and deontic uses of the English modal verb must:
An ambiguous case is You must speak Spanish. The primary meaning would be the deontic meaning but this may be intended epistemically
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:

English

The following table lists the modal auxiliary verbs of standard English and various senses in which they are used:
The verbs in this list all have the following characteristics:
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 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 as are be, do, and have, but unlike those three verbs, they are grammatically defective. For example, havehas vs. should*shoulds and dodid vs. may*mayed, etc. In clauses that contain two or more verbs, any modal that is present always appears leftmost in the verb catena. 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.,
Such limits in form 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. 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. Since modal verbs are auxiliary verbs as is do, in questions and negations they appear in the word order the same as do.
normal verbmodal verb
affirmativehe workshe can work
negationhe does not workhe cannot work
emphatiche does work hardhe can work hard
questiondoes he work here?can he work at all?
negation + questiondoes he not work here?can he not work at all?

Some form of auxiliary "do" occurs in all West Germanic languages except Afrikaans. Its occurrence in the Frisian languages is restricted to Saterland Frisian, where it may be a loan from Low German. In both German and Dutch, the construction has been known since the Middle Ages and is common in dialects, but is considered ungrammatical in the modern standard language. The Duden lists the following three potential uses of tun in modern German, with only the first being considered standard:
exampleEnglish translation
verb topicalizationEssen tue ich schon immer am Liebsten.To eat I've always liked the most.
present/future auxiliaryIch tu bloß schnell die Blumen gießen.I'll just quickly water the flowers
subjunctive auxiliaryDas täte mich schon interessieren.That would certainly interest me

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.
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 English, Afrikaans, Danish, and Swedish, the plural and singular forms are identical. For German, Dutch, Low Saxon, West Frisian, Faroese and Gothic, both a plural and a singular form of the verb are shown. Forms within parentheses are obsolete, rare, and/or mainly dialectal in the modern languages.
EnglishGermanDutchLow SaxonWest FrisianAfrikaansDanishSwedishFaroeseGothic
cankönnen, kannkunnen, kankönen, kannkinne, kinkankankankunna, kannkunnum, kann
shallsollen, sollzullen, zalschölen, schallsille, silsalskalskaskula, skalskulum, skal
willwollen, willwillen, wilwüllen, willwolle, wolwilvilvillvilja, vilwileima, wiljau
, mustmüssen, mussmoeten, moetmöten, muttmoatte, moatmoetmåstemåste?-,gamōt
maymögen, magmogen, magmögen, magmeie, meimag'mega, mámagum, mag
wissen, weißweten, weet??weetvedvetvita, veitwitum, wait
dürfen, darfdurven, durfdörven, dörvdoarre, doardurf?'?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. 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, and a non-modal use. The Dutch, West Frisian, and Afrikaans verbs durven, doarre, and durf are not considered modals 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 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 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 verbmodal verb
Englishhe workshe can
Germaner arbeiteter kann
Dutchhij werkthij kan
Low Saxonhe warkthe kann
West Frisianhy wurkethy kin
Afrikaanshy werkhy kan
Danishhan arbejderhan kan
Swedishhan arbetarhan kan
Faroesehann arbeiðirhann kann
Gothicis waurkeiþis kann

The main verb that is modified by the modal verb is in the infinitive form and is not preceded by the word to. There are verbs that may seem somewhat similar in meaning to modal verbs, but the construction with such verbs would be different:
normal verbmodal verb
Englishhe tries to workhe can work
Germaner versucht zu arbeitener kann arbeiten
Dutchhij probeert te werkenhij kan werken
Low Saxonhe versöcht to warkenhe kann warken
West Frisianhy besiket te wurkjehy kin wurkje
Afrikaanshy probeer om te werkhy kan werk
Gothicis sokeiþ du waurkjanis kann waurkjan

Similarly, in North Germanic languages, the infinitive marker is not used for main verbs with modal auxiliaries: Han kan arbejde, han kan arbeta, hann kann arbeiða. However, there also are some other constructions where the infinitive marker need not be employed, as in Swedish han försöker arbeta.

Less defective

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 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 modal verbs have infinitive forms. This for instance enables catenae containing several modal auxiliaries. The modal verbs are underlined in the following table.
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 other languages

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 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

, 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. 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

, 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", devoir "to have an obligation", and vouloir "to want".

Italian

Modal verbs in Italian Italian form a distinct class. They can be easily recognized by the fact that they are the only group of verbs that does not have a fixed auxiliary verb for forming the perfect, but they can inherit it from the verb they accompany – Italian can have two different auxiliary verbs for forming the perfect, avere, and essere. There are in total four modal verbs in Italian: potere, volere, dovere, sapere. Modal verbs in Italian are the only group of verbs allowed to follow this particular behavior. When they do not accompany other verbs, they all use avere as helping verb for forming the perfect.
For example, the helping verb for the perfect of potere is avere, as in ho potuto ; nevertheless, when used together with a verb that has as auxiliary essere, potere inherits the auxiliary of the second verb. For example: ho visitato il castello / ho potuto visitare il castello ; but sono scappato / sono potuto scappare.
Note that, like in other Romance languages, there is no distinction between an infinitive and a bare infinitive in Italian, hence modal verbs are not the only group of verbs that accompanies an infinitive. Thus, while in English a modal verb can be easily recognized by the sole presence of a bare infinitive, there is no easy way to distinguish the four traditional Italian modal verbs from other verbs, except the fact that the former are the only verbs that do not have a fixed auxiliary verb for the perfect. For this reason some grammars consider also the verbs osare, preferire, desiderare, solere as modal verbs, despite these always use avere as auxiliary verb for the perfect.

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:
The complete list of modal auxiliary verbs consists of
, like French, uses fully conjugated verbs followed by infinitives. For example, poder "to be able", deber "to have an obligation", and querer "to want".
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.