AUX auxiliary auxiliary [Lat. auxiliaris ‘giving aid’] (also AUX, helping verb)

Subcategory of verbs which can be distinguished from main verbs by semantic and syntactic criteria. Auxiliaries have a reduced lexical meaning (cf. have, will, be). Their valence is different from main verbs, since they do not select nominal arguments but rather main verbs as their argument. Auxiliaries typically occur as exponents of morphological categories such as tense, mood, voice, number, and person. In English, auxiliaries allow the so-called subject-auxiliary inversion in certain constructions, e.g. Caroline has eaten vs Has Caroline eaten? It is a matter of debate whether these differences from main verbs are sufficient to treat auxiliaries as separate categories. Within earlier versions of transformational grammar, auxiliaries were treated as verbs with the feature AUX. In more recent generative grammar models the exponent of verbal inflection is a separate node called INFL ( INFL node). Occasionally modal verbs and copular verbs are subsumed under the category auxiliary ( modal auxiliary).