grammaticalise

Grammaticalise (also grammaticalize) is a term in historical and functional linguistics describing the process by which a word or construction acquires grammatical function or category. It is a central concept in grammaticalization theory, which studies how lexical items become affixes, clitics, or function words over time.

The process typically involves semantic bleaching (loss or narrowing of the original lexical meaning), phonological reduction, and reanalysis of the item as a grammatical marker. As grammaticalisation proceeds, the form may shift in position or distribution, become a bound morpheme or clitic, and eventually function as an auxiliary or other grammatical marker. The direction of change is usually from a content word to a function word or marker, though cross-linguistic variation exists and reversals are occasionally discussed in the literature.

Well-known examples include the English future marker will, which originated as a verb meaning “wish” or “be willing” and later became the future tense auxiliary. Another case is the periphrastic future going to, derived from the motion verb go plus an infinitive. Do-support in English also illustrates how an auxiliary can arise from an originally lexical do. Across languages, grammaticalisation helps explain the emergence of determiners, auxiliaries, markers of tense or aspect, and other functional categories from more concrete lexical sources.

Grammaticalisation is a foundational concept for understanding diachronic change, language change mechanics, and the evolution of morphosyntactic systems, influencing approaches to typology, contact-induced change, and creolization.