Auxiliary verb

In linguistics, an auxiliary or helping verb is a verb whose function it is to give further semantic or syntactic information about the main or full verb which follows it. In English, the extra meaning an auxiliary verb imparts alters the basic form of the main verb to have one or more of the following functions: passive, progressive, perfect, modal, or dummy.

Introduction

In stricter linguistic terms than the simple definition above:

Every clause has a finite verb which consists of a full verb (a non-auxiliary verb) and optionally one or more auxiliary verbs, each of which is a separate word. Examples of finite verbs include write (no auxiliary verb), have written (one auxiliary verb), and have been written (two auxiliary verbs).

There is a syntactic difference between an auxiliary verb and a full verb; that is, each has a different grammatical function within the sentence. In English, and in many other languages, there are some verbs that can act either as auxiliary or as full verbs, such as be ("I am writing a letter" vs "I am a postman") and have ("I have written a letter" vs "I have a letter"). In the case of be, it is sometimes ambiguous whether it is auxiliary or not; for example, The ice cream was melted could mean either Someone/something melted the ice cream (in which case melt would be the main verb) or the ice cream was mostly liquid (in which case be would be the main verb).

Functions of the English auxiliary verb

Passive voice

The auxiliary verb be is used with a past participle to form the passive voice; for example, the clause "the door was opened" implies that someone (or something) opened it, without stating who (or what) it was. Because many past participles are also stative adjectives, the passive voice can sometimes be ambiguous; for example, "at 8:25 PM, the window was closed" can be a passive-voice sentence meaning "at 8:25 PM, someone closed the window," or a non-passive-voice sentence meaning "at 8:25 PM, the window was not open". Perhaps due to this ambiguity, the verb get will sometimes be used colloquially instead of be in forming the passive voice.

Progressive aspect

The auxiliary verb be is used with a present participle to form the progressive aspect; for example, the sentence "I am doing my homework" describes what the speaker is doing at the very moment of utterance, while the sentence "I do my homework" is a temporally broader statement.

Perfect aspect

The auxiliary verb have is used with a past participle to form the perfect aspect; for example, the sentence "Peter has fallen in love" differs from "Peter fell in love" in that the former implies some connection to the present — likely that Peter is still in love — while the latter does not.

Modal

There are nine modal verbs: can/could, may/might, shall/should, will/would and must. They differ from the other auxiliaries both in that they are defective verbs, and in that they can never function as main verbs. They express the speaker's (or listener's) judgement or opinion at the moment of speaking. Some of the modal verbs have been seen as a conditional tense form in English.

Some schools of thought consider could to represent the past tense of can. However, according to Michael Lewis (The English Verb), this is not always true. "Could I get you something?" clearly is not expressing Past Time. Lewis instead suggests that could is a remote form of can. It is evident after re-examining the usage of could in this light that remoteness does describe the general meaning, e.g.

I couldn't do it. (remoteness of time)
It could happen. (remoteness of possibility)
Could you do me a favor? (remoteness of relationship)

The remaining modal auxiliaries can be viewed in this same manner. Lewis covers this area in detail in his book, see reference.

Dummy

Because, aside from the verb to be (or to have in British English), only auxiliaries can be inverted to form questions and only auxiliaries can take negation directly, a dummy auxiliary do is used for questions and negatives when only a full verb exists in the positive statement (i.e. there are no auxiliaries in the positive, non-interrogative form). The same dummy do is used for emphasis in the positive statement form. This is known as do-insertion.

For example, if the positive statement form is:

I know the way.

the interrogative, negative and emphatic forms are respectively:

Do you know the way?
I don't know the way.
I do know the way.

Compare this with:

I should know the way.
Should I know the way?
I shouldn't know the way.
(and the emphatic form has to be marked by intonation or punctuation).

Quasi-auxiliaries

English contains many verb phrases that function as quasi-auxiliaries, such as be going to, used to, is about to. These quasi-auxiliaries require an infinitive. Others take a gerund (e.g. need, as in need fixing, in American English), past participle (e.g. get, as in get done), or other verb form

Properties of the English auxiliary verb

Negation

Auxiliaries take not (or n't) to form the negative, e.g. can't, won't, shouldn't, etc. In certain tenses, in questions, when a contracted auxiliary verb can be used, the position of the negative particle n't moves from the main verb to the auxiliary: cf. Does it not work? and Doesn't it work?

Inversion

Auxiliaries invert to form questions:

You will come.
Will you come?

Emphasis

The dummy auxiliary do is used for emphasis in positive statements (see above):

I do like this beer!

Ellipsis

Auxiliaries can appear alone where a main verb has been omitted, but is understood:

John never sings, but Mary does ^*.

Tag questions

Auxiliaries can be repeated at the end of a sentence, with negation added, to form a tag question.

You will come, won't you?
You ate, didn't you?

Other languages

Some languages use "be" for the perfect forms of some or all verbs, instead of "have" (in Esperanto, for example, Mi estis irinta = I was having-gone = I had gone). French, German, and Dutch use it for verbs of motion and becoming, and (in German and Dutch) for "to be" itself, as does Italian. The use of auxiliaries is one variation among Romance languages. Finnish uses ole for all verbs: "Sillä niin on Jumala maailmaa rakastanut" (Because so much is God the world loved). English uses "be" only with "go" in some senses.

Reference

The English Verb 'An Exploration of Structure and Meaning', Michael Lewis. Language Teaching Publications. ISBN 0-906717-40-X

Parts of speech | Verb types

Gourt Home::Gourt :: Auxiliary verb