infix

Infix is a human-made classificatory map within linguistic theory that identifies a bound morpheme inserted within the interior of a word stem, splitting the stem into two parts that bracket the inserted element. Three parameters carve the construct: (1) boundness — the infix is a bound morpheme, not an independent word, which separates it from tmesis; (2) interior position — the infix attaches inside the stem rather than at its periphery, distinguishing it from prefixes (pre-stem), suffixes (post-stem), and circumfixes (both edges); (3) morphophonological specificity — in languages where infixation is productive, the infix attaches at a fixed position determined by the stem's internal structure. Paradigmatic case: Tagalog actor-focus infix -um- (kain becomes k-um-in). The category persists as a stable term in the morphological inventory of languages that employ infixation and as a descriptive label in comparative linguistic typology. [formal: infixus | substrate: mind | horizon: generations | explicit: yes | epoch: 0.01]