Iotacism (Greek: ιωτακισμός, iotakismos) or itacism is the process of vowel shift by which a number of vowels and diphthongs converged towards the pronunciation [i] in post-classical Greek and Modern Greek. The term "iotacism" refers to the letter iota, the original sign for [i], with which these vowels came to merge. The alternative term itacism refers to the new pronunciation of the name of the letter eta as [ˈita] after the change.