Auxiliary Verb - Auxiliary Verbs Vs. Light Verbs

Auxiliary Verbs Vs. Light Verbs

Some syntacticians distinguish between auxiliary verbs and light verbs. The two are similar insofar as both verb types contribute mainly just functional information to the clauses in which they appear. Hence both do not qualify as separate predicates, but rather they form part of a predicate with another expression - usually with a full verb in the case of auxiliary verbs and usually with a noun in the case of light verbs.

In English, light verbs differ from auxiliary verbs in that they cannot undergo inversion and they cannot take not as a postdependent. The verbs have and do can function as auxiliary verbs or as light verbs (or as full verbs). When they are light verbs, they fail the inversion and negation diagnostics for auxiliaries, e.g.

a. They had a long meeting.

b. *Had they a long meeting?

c. *They had not a long meeting.

a. She did a report on pandering politicians.

b. *Did she a report on pandering politicians?

c. *She did not a report on pandering politicians.

(In some cases, though, have may undergo auxiliary-type inversion and negation even when it is not used as an auxiliary verb – see Subject–auxiliary inversion: Inversion with other types of verb.)

Sometimes the distinction between auxiliary verbs and light verbs is overlooked or confused. Certain verbs (e.g. used to, have to, etc.) may be judged as light verbs by some authors, but as auxiliaries by others.