Modal Auxiliary verb

An auxiliary verb (abbreviated aux) is a verb that adds functional or grammatical meaning to the clause in which it appears, such as to express tense, aspect, modality, voice, emphasis, etc. Auxiliary verbs usually accompany a main verb. The main verb provides the main semantic content of the clause.[1] An example is the verb have in the sentence I have finished my lunch. Here, the main verb is finish, and the auxiliary have helps to express the perfect aspect. Some sentences contain a chain of two or more auxiliary verbs. Auxiliary verbs are also called helping verbs, helper verbs, or (verbal) auxiliaries. Basic examples Edit Below are some sentences that contain representative auxiliary verbs from English, Spanish, German, and French, with the auxiliary verb marked in bold: a. Do you want tea? – do is an auxiliary accompanying the main verb want, used here to form a question – see do-support. b. He has given his all. – has is an auxiliary used in expressing the perfect aspect of give. c. He cogido tu lápiz. – he is an auxiliary accompanying the main verb coger, used here to form a compound verb, the perfect present of the verb coger.[2] (I) have grabbed your pencil = 'I have taken your pencil.' d. Das wurde mehrmals gesagt. – wurde 'became' is an auxiliary used to build the passive voice in German.[3] That became many times said = 'That was said many times.' e. Sie ist nach Hause gegangen. – ist 'is' is an auxiliary used with movement verbs to build the perfect tense/aspect in German.[4] She is to home gone = 'She went home/She has gone home.' f. J'ai vu le soleil. – ai 'have' is an auxiliary used to build the perfect tense/aspect in French.[5] I have seen the sun = 'I have seen the sun/I saw the sun.' f. Nous sommes hébergés par un ami. – sommes 'are' is an auxiliary used to build the passive voice in French.[6] We are hosted by a friend. These auxiliaries help express a question, show tense/aspect, or form passive voice. Auxiliaries like these typically appear with a full verb that carries the main semantic content of the clause. Traits across languages In English Edit Main article: English auxiliaries and contractions The following sections consider auxiliary verbs in English. They list auxiliary verbs, then present the diagnostics that motivate this special class (subject-auxiliary inversion and negation with not). The modal verbs are included in this class, due to their behavior with respect to these diagnostics. List of auxiliaries in English Edit A list of verbs that (can) function as auxiliaries in English is as follows:[10] be (am, are, is, was, were, being, been), can, could, dare, do (does, did), have (has, had, having), may, might, must, need, ought, shall, should, will, would The status of dare, need (not), and ought (to) is debatable[11] and the use of these verbs as auxiliaries can vary across dialects of English. If the negative forms can't, don't, won't, etc. are viewed as separate verbs (and not as contractions), then the number of auxiliaries increases. The verbs do and have can also function as full verbs or as light verbs, which can be a source of confusion about their status. The modal verbs (can, could, may, might, must, shall, should, will, would, and dare, need and ought when included) form a subclass of auxiliary verbs. Modal verbs are defective insofar as they cannot be inflected, nor do they appear as gerunds, infinitives, or participles. The following table summarizes the auxiliary verbs in standard English and the meaning contribution to the clauses in which they appear. Many auxiliary verbs are listed more than once in the table based upon discernible differences in use. Auxiliary verb Meaning contribution Example be1 copula (= linking verb) She is the boss. be2 progressive aspect He is sleeping. be3 passive voice They were seen. can1 deontic modality I can swim. can2 epistemic modality Such things can help. could1 deontic modality I could swim. could2 epistemic modality That could help. dare deontic modality I dare not attempt it. do1 do-support/emphasis You did not understand. do2 question Do you like it? have perfect aspect They have understood. may1 deontic modality May I stay? may2 epistemic modality That may take place. might epistemic modality We might give it a try. must1 deontic modality You must not mock me. must2 epistemic modality It must have rained. need deontic modality You need not water the grass. ought deontic modality You ought to play well. shall deontic modality You shall not pass. should1 deontic modality You should listen. should2 epistemic modality That should help. will1 epistemic modality We will eat pie. will2 future tense The sun will rise tomorrow at 6:03. will3 habitual aspect He will make that mistake every time. would1 epistemic modality Nothing would accomplish that. would2 future-in-the-past tense After 1990, we would do that again. would3 habitual aspect Back then we would always go there. Deontic modality expresses an ability, necessity, or obligation that is associated with an agent subject. Epistemic modality expresses the speaker's assessment of reality or likelihood of reality. Distinguishing between the two types of modality can be difficult, since many sentences contain a modal verb that allows both interpretations. Diagnostics for identifying auxiliary verbs in English Edit The verbs listed in the previous section can be classified as auxiliaries based upon two diagnostics: they allow subject–auxiliary inversion (the type of inversion used to form questions etc.) and (equivalently) they can take not as a postdependent (a dependent that follows its head). The following examples illustrate the extent to which subject–auxiliary inversion can occur with an auxiliary verb but not with a full verb:[12] a. He was working today. b. Was he working today? - Auxiliary verb was allows subject–auxiliary inversion. a. He worked today. b. *Worked he today? - Full verb worked does not allow subject–auxiliary inversion. a. She can see it. b. Can she see it? - Auxiliary verb can allows subject–auxiliary inversion. a. She sees it. b. *Sees she it? - Full verb sees does not allow subject–auxiliary inversion. (The asterisk * is the means commonly used in linguistics to indicate that the example is grammatically unacceptable or that a particular construction has never been attested in use.) The following examples illustrate that the negation not can appear as a postdependent of a finite auxiliary verb, but not as a postdependent of a finite full verb:[13] a. Sam would try that. b. Sam would not try that. - The negation not appears as a postdependent of the finite auxiliary would. a. Sam tried that. b. *Sam tried not that. - The negation not cannot appear as a postdependent of the finite full verb tried. a. Tom could help. b. Tom could not help. - The negation not appears as a postdependent of the finite auxiliary could. a. Tom helped. b. *Tom helped not. - The negation not cannot appear as a postdependent of the finite full verb helped. A third diagnostic that can be used for identifying auxiliary verbs is verb phrase ellipsis. Auxiliary verbs can introduce verb phrase ellipsis, but main verbs cannot.[citation needed] See the article on verb phrase ellipsis for examples. These criteria lead to the copula be and non-copular use of be as an existential verb being considered an auxiliary (it undergoes inversion and takes postdependent not, e.g., Is she the boss?, She is not the boss, Is there a God?, There is a God). However, if one defines auxiliary verb as a verb that somehow "helps" another verb, then the copula be is not an auxiliary, because it appears without another verb. The literature on auxiliary verbs is somewhat inconsistent in this area.[14] There are also some properties that some but not all auxiliary verbs have. Their presence can be used to conclude that the verb is an auxiliary, but their absence does not guarantee the converse. One such property is to have the same form in the present tense, also for the first and the third person singular. This in particular is typical for modal auxiliary verbs, such as will and must. (Examples: He will come tomorrow, she must do it at once, not he wills or she musts.)