Diastole

An Introduction to Diastole

Diastole (etymologically from Greek, also known as “ectasis”), is a rhetorical device which consists in lengthening out a vowel soundOpens in new window or syllableOpens in new window that is naturally short.

In other words, a syllable naturally short, is made long; for example: “Oooooh yeah!”. Diastole is the opposite of systoleOpens in new window.

Diastole is sometimes employed for the sake of meterOpens in new window, and may result (in English) in the shifting of accent from one syllable to another. — (Silva Rhetocae)

Classic Example
  • I know thee well; a serviceable villain,
    (Shakespeare, King Lear 4.6.251)
  • The third syllable of “serviceable” is normally short, but as this word occurs in the following line of iambic pentameter, that syllable is lengthened because it takes the stress of the meter's rhythm (stressed syllables are bolded, and the lengthened vowel sound is italicized).
Further Readings:
Silver Rhetoricae | Figures: DiastoleOpens in new window
Dictionary of Rhetorical Terms (By Gregory T. Howard) | DiastoleOpens in new window
Susenbrotus (“diastole,” “ectasis” [1540] 22); Sherry (“ectasis,” “extension” [1550] 27).