The present study deals with the phonological system of three Iranian Balochi dialects namely Mrijaveh Sarhaddi Balochi (MSB), Sarawani Balochi (SB) and Lashari Balochi (LB). Those three selected Iranian Balochi dialects are spoken respectively in Mirjaveh, Sarawan, and Lashar in Sistan and Baluchestan province, which is located in the southeast of Iran. As to the title of the present research, both descriptive and theoretical approaches (Optimality Theory) are concerned, since they can complement each other, connecting language (i.e. Balochi) to Language (i.e. universal grammar), and give a formal and precise description and analysis of the grammatical properties of Iranian Balochi dialects sounds.