The relationship between semantics and phonology is generally denied (Archangeli & Pulleyblank, 1994: 5, 433). That is, semantic and phonological changes usually apply independently. Phonological processes of Persian which convert a phonemic representation to its phonetic representation mostly do not involve any meaning changes. However, there are few idiosyncratic words in Persian whose phonetic representations which are used in the colloquial style differ in meaning from their phonemic representations.Various types of semantic changes including extensionand restriction of meaning or both, in addition to pragmatic changes occur in these words. In some cases the meaning changes accompany a change in spelling too. This research addresses phonology-semantics interaction using “lexical-access constraints” (Boersma, 2001), in optimality theory as the sole theory to make the analysis of phonology-semantics interaction to some extent possible. Furthermore, some of these interactions occur to save energy and to make less muscular effort. This is usually discussed in functional rather than formal approaches. Following Kirchner (1989) this research integrates functionalism and formalism in optimality theory to deal with this issue.