 Verb

A verb is a part of speech that commonly organizes a clause, specifying relationships among its participants and contributing an event or state description. Forms of a verb may express grammatical tense, grammatical aspect or grammatical agreement, though the mechanisms differ across languages.^[ref]

Compare Rin sleeps with Rin opens the box. The second construction contains an object in addition to its subject; knowing a verb includes knowing how it combines with other expressions. Calling verbs “action words” misses examples such as know, which describes a state.

An annotation scheme must also define its boundaries. Universal Dependencies assigns main verbs the label VERB while distinguishing auxiliary uses with AUX. Thus a traditional grammatical description and a particular computational tag inventory need not draw every boundary identically. Stating the scheme makes category counts in a text corpus interpretable.