The Role of Phonological Strength in the Occurrence of Fortition Processes in Persian Languages Based on the Approaches of Foley and Vennemann

Phonologists have spoken about lenition and fortition for more than a century; in fact, for as long as phonology has existed. The first scientific terminology that was introduced in the 19th century in order to talk about manner distinctions is based on the intuition that sounds naturally range on a scale which expresses strength.This paper studies the role of phonological strength in the occurrence of fortition processes in Persian language. The fortition processes of glide occlusivization, glide fricativization, glide affrication and buccalization according to the concepts of «positional strength», «assimilative strength» and «the inertial development principle» (Foley, 1977), and «the preference laws for syllable structure» (Vennemann, 1988) are analyzed.The questions posed in the present study are: 1- In the occurrence of each of the processes of glide occlusivization, glide fricativization, glide affrication, and devoicing and buccalization, which of the factors mentioned in the Foley approach (1977) have a role? 2- To what extent have the mentioned processes been done in order to improve the structure of the syllable according to the " the preference laws for syllable structure" (Vennemann, 1988)? 3- What is the explanation for the role of "phonological strength" in the emergence of Persian language strengthening processes?