Compensatory lengthening in phonology and historical linguistics is the lengthening of a vowel sound that happens upon the loss of a following consonant, usually in the syllable coda. An example from the history of English is the lengthening of vowels that happened when the voiceless velar fricative was lost. For example, in Chaucer's time the word night was pronounced ; later the was lost and the was lengthened to by compensatory lengthening. (Later the became by the Great Vowel Shift.)

Phonology | Historical linguistics

allongement compensatoire | 代償延長