عنوان مقاله [English]
The purpose of this article is to investigate the process of weakness in vocabularies from Middle Persian to Dari Persian based on generative phonology framework. The presented data of this article have been extracted from vocabularies of the middle-Persian Zoroastrian mentioned in Concise Pahlavi Dictionary from David Neil Mackenzie (1388), which have been found in Persian Dari. Then, their different forms have been found in the dictionaries of Persian Dari including Dehkhoda (1388), Hassan Doost (1383), and about Persian Dictionaries (1382-1388), as well as in New Persian. In each of these languages, their phonological rules are extracted and listed. In the next step, the phonological analyses of the rules have been investigated based on the principles of generative phonology and the criteria of Jensen (2004: 117) to discover the natural rule. Three types of processes of weakness have been investigated in this paper. In this article, authors have examined these three types of weakness. Some of the results are: (1) the most natural rule isn’t necessarily the most simple one; on the other hand, the simplicity is the necessary condition for naturalness of rules, but it isn’t sufficient condition. 2) According to the analyses, the weakness process has been seen in coda, final-word , intervocalic and postvocalic type more than onset and initial- word. 3). Consonants, which participate in this process in according to rules, are obstruent consonants such as [p, b, f, k, g, w, t, d]. 4) Phonological rules usually act unidirectional.