Affixes

Affixes are morphemes attached to a word stem to modify its meaning or grammatical function. They are bound morphemes, meaning they cannot stand alone, and they attach to roots or bases to form new words or to express grammatical information. Affixes come in several positions: prefixes attach at the front, suffixes at the end, infixes insert within the base, and circumfixes wrap around the word (a prefix plus a suffix).

Affixation serves two broad functions: derivational and inflectional. Derivational affixes create new lexical items or classes, often changing part of speech, as in happy → happiness or teach → teacher. Inflectional affixes signal grammatical information such as tense, number, case, mood, or person, without changing core meaning, as in walk → walks, walked, walking.

In different languages the balance and productivity of affixes vary. Some languages are agglutinative, piling up many affixes with clear boundaries, as in Turkish or Finnish. Others are fusional, combining several grammatical categories into single affixes, as in Latin or Russian. Some languages use infixes or circumfixes, while others rely mainly on prefixes and suffixes.

The study of affixes, morphology, includes allomorphy (alternative shapes of an affix depending on phonology), phonological changes, and interactions with stems during word formation. Affixes interact with phonology and syntax, and affixation plays a central role in the structure of words across languages.