Auxiliary verb abbreviated aux

An auxiliary verb (abbreviated aux) is a verb that adds functional or grammatical meaning to the clause in which it occurs, so as to express tense, aspect, modality, voice, emphasis, etc. Auxiliary verbs usually accompany an infinitive verb or a participle, which respectively provide the main semantic content of the clause. An example is the verb have in the sentence I have finished my lunch. Here, the auxiliary have helps to express the perfect aspect along with the participle, finished. Some sentences contain a chain of two or more auxiliary verbs. Auxiliary verbs are also called helping verbs, helper verbs, or (verbal) auxiliaries. Research has been conducted into split inflection in auxiliary verbs.

asic examples

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 infinitive, want, used here to form a question – see do-support.

b. He has given his all. – have, from which has is inflected, is an auxiliary used in expressing the perfect aspect of give.

c. He cogido tu lápiz. – he is an auxiliary accompanying the infinitive coger, used here to form a verb phrase, the perfect present in Spanish.

(I) have grabbed your pencil = 'I have taken your pencil.'

d. Das wurde mehrmals gesagt. – werden, from which wurde is inflected, become is an auxiliary used to build the passive voice in German.

That became many times said = 'That was said many times.'

e. Sie ist nach Hause gegangen. – sein, from which ist is inflected, 'be' is an auxiliary used with movement verbs to build the perfect tense/aspect in German.

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.

I have seen the sun = 'I have seen the sun/I saw the sun.'

g. Nous sommes hébergés par un ami. – sommes, from which être is inflected, 'be' is an auxiliary used to build the passive voice in French.

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

Auxiliary verbs typically help express grammatical tense, aspect, mood, and voice. They generally appear together with an infinitive. The auxiliary is said to "help" the infinitive. The auxiliary verbs of a language form a closed class, i.e., there is a fixed, relatively small number of them.

Widely acknowledged verbs that can serve as auxiliaries in English and many related languages are the equivalents of be to express passive voice, and have (and sometimes be) to express perfect aspect or past time reference.

In some treatments, the copula be is classed as an auxiliary even though it does not "help" another verb, e.g.,

The bird is in the tree. – is serves as a copula with a predicative expression not containing any other verb.

Definitions of auxiliary verbs are not always consistent across languages, or even among authors discussing the same language. Modal verbs may or may not be classified as auxiliaries, depending on the language. In the case of English, verbs are often identified as auxiliaries based on their grammatical behavior, as described below. In some cases, verbs that function similarly to auxiliaries, but are not considered full members of that class (perhaps because they carry some independent lexical information), are called semi-auxiliaries. In French, for example, verbs such as devoir (have to), pouvoir (be able to), aller (be going to), vouloir (want), faire (make), and laisser (let), when used together with the infinitive of another verb, can be called semi-auxiliaries. There has also been a study on auxiliary verb constructions in Dravidian languages.

In English

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.