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This page pertains to UD version 2.

AUX: auxiliary verb


An auxiliary is a function word that accompanies the lexical verb of a verb phrase and expresses grammatical distinctions not carried by the lexical verb, such as person, number, tense, mood, aspect, voice or evidentiality. It is often a verb (which may have non-auxiliary uses as well) but many languages have nonverbal TAME markers and these should also be tagged AUX. The class AUX also include copulas (in the narrow sense of pure linking words for nonverbal predication).

Modal verbs may count as auxiliaries in some languages (English). In other languages their behavior is not too different from the main verbs and they are thus tagged VERB.

Note that not all languages have grammaticalized auxiliaries, and even where they exist the dividing line between full verbs and auxiliaries can be expected to vary between languages. Exactly which words are counted as AUX should be part of the language-specific documentation.

In Bulgarian the auxiliary verbs are varieties of the verb ‘to be’ in both functions – auxiliary and copular:

Modal verbs count as main verbs in BulTreeBank tagset and they are thus tagged VERB.

Also, the following verbal particles (Tx) are viewed as auxiliaries:


Note that the symbol `#’, used in the Universal POS section indicates a holder for arbitrary number of features, suppressed in the respective tag as irrelevant in the BulTreeBank tagset, when mapped to the Universal one.

AUX in other languages: [bej] [bg] [bm] [cs] [cy] [da] [el] [en] [et] [fi] [fro] [fr] [ga] [grc] [gub] [hu] [hy] [it] [ja] [kk] [kpv] [myv] [no] [pcm] [pt] [qpm] [ru] [sl] [sv] [tr] [tt] [uk] [u] [urj] [yue] [zh]