The Collaborative International Dictionary of English v.0.48:

Mispronunciation \Mis`pro*nun`ci*a"tion\ (? or ?), n.
   Wrong or improper pronunciation.
   [1913 Webster]

WordNet (r) 3.0 (2006):

mispronunciation
    n 1: incorrect pronunciation

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "mispronunciation":
   Irish bull, anacoluthon, bull, cacoepy, cacology, catachresis,
   corruption, fluff, folk etymology, gammacism, grammatical error,
   hypercorrection, hyperform, lambdacism, malaprop, malapropism,
   marrowsky, missaying, misspeaking, misusage, mytacism,
   paralambdacism, pararhotacism, rhotacism, solecism, spoonerism