Fortition

Fortition is a term in historical phonology describing a process by which consonants become stronger or more obstruent, in contrast with lenition, which weakens them. Fortition involves changes that increase articulatory effort or constriction, producing stronger or more distinct consonants. Common manifestations include the introduction or strengthening of aspiration in stops, devoicing of voiced segments, glottalization, and the use of ejectives or other fortis articulations. It can also involve converting a fricative into a more constricted sound or turning a simple stop into a stronger affricate in some environments.

Fortition operates through several mechanisms. Stops may gain aspiration (p to pʰ, t to tʰ, k to kʰ); previously voiced stops may become voiceless; glottal stops may replace oral stops or accompany them; ejectives or other fortis articulations may be introduced; and some fricatives can shift toward more constricted, affricate-like consonants. Fortition can arise from various triggers, including phonotactic pressures to preserve contrasts, morphological reorganization, or language contact, where speakers favor stronger consonants in borrowing or adoption.

Notable examples discussed in literature include the emergence of aspirated stops in certain language families and the presence of ejective stops in Caucasian languages, which are often described as fortis or strengthened consonants. Fortition is one of several diachronic pathways studied to understand how consonant inventories evolve and how phonemic distinctions are maintained or expanded.

See also: lenition, phonology, historical linguistics.