IsochronyIsochrony is the postulated rhythmic division of time into equal portions by a language. Rhythm is an aspect of prosody, others being intonation, stress, and tempo of speech. Three alternative ways in which a language can divide time are postulated: The duration of every syllable is equal (syllable-timed); The duration of every mora is equal (mora-timed). The interval between two stressed syllables is equal (stress-timed). The idea was first expressed thus by Kenneth L.