Anaptyxis: A form of epenthesis.

Anaptyxis involves inserting a prop vowel into a consonant cluster, simplifying the pronunciation.

A common example in English is in the pronunciation of "nuclear" as "nucular" (though this may also be read as metathesis.) Also often in foreign names, such as "connect" for "Knecht" or "Devorak" for "Dvorak".

From the Greek word αναπτυξις, "opening, unfolding".