The word mischievous has three syllables, mis-chie-vous,
with the stress on the first syllable: [mis-chuh-vuh s] /ˈmɪs tʃə vəs/ (Show IPA).
There is a common tendency to shift the stress to the second syllable and say or write the word as if there were an extra letter i
after the v,
turning it into a four-syllable word: [mis-chee-vee-uh s] /mɪsˈtʃi vi əs/ .
These alterations of the pronunciation (and sometimes even the spelling) may occur in part because in many English words ie
is pronounced like ee,
as in chief,
in part because many words end with [-ee-uh s] /-i əs/
spelled either -ious
(as in devious
) or -eous
(as in aqueous
), and in part because of confusion over where the second i
in the word belongs. The Oxford English Dictionary reports that for some time in the evolution of the word—from about the sixteenth to the eighteenth century— mischievious
was actually a fairly standard alternative spelling. Today, however, both the four-syllable spelling and the four-syllable pronunciation are generally regarded as nonstandard.