Shiraz University Journal of Iranian Dialects Linguistics 2538-3574 Articles in Press 2021 07 12 The Phonological Strength Approach to the lenition of Oral Plosives in Persian Language Based on Foleyʹs Historical View The Phonological Strength Approach to the lenition of Oral Plosives in Persian Language Based on Foleyʹs Historical View 6227 10.22099/jill.2021.40495.1250 FA Zeinab Mohammad Ebrahimi Jahromi assistant professor of linguistics Linguistic Department, Faculty of Letters and Humanities ,Shahid Beheshti University Zahra Karimi Bavayani P.HD student of linguistics, Shahid Beheshti university Aliye A.Z.Kambuzia associated professor of linguistics. Tarbyat Moddares university Journal Article 2021 04 28 Lenition, is a phonological process in which, a phonological segment is produced more weakly or become more sonorous. This term is often developed to any other phonological processes which show weakening. This research studies the role and the type of phonological strength rules on occurring lenition processes in Persian language in its evolution from the middle Persian to the modern Persian based on Foleyʹs historical view. To do this, 120 Middle Persian words were selected from different Pahlavi dictionaries and were analyzed. <br>One of the research findings is that the elision at the end of the word and fricativization at the beginning of it, between two vowels and the coda of the syllable (before the continuant consonants of the onset of the next syllable), have been applied to plosive consonants. Another achievement of this research is that the plosive lenition has been accompanied by two successive processes of "increasing of the sonority" and "opening of the articulatory stricture". Lenition, is a phonological process in which, a phonological segment is produced more weakly or become more sonorous. This term is often developed to any other phonological processes which show weakening. This research studies the role and the type of phonological strength rules on occurring lenition processes in Persian language in its evolution from the middle Persian to the modern Persian based on Foleyʹs historical view. To do this, 120 Middle Persian words were selected from different Pahlavi dictionaries and were analyzed. <br>One of the research findings is that the elision at the end of the word and fricativization at the beginning of it, between two vowels and the coda of the syllable (before the continuant consonants of the onset of the next syllable), have been applied to plosive consonants. Another achievement of this research is that the plosive lenition has been accompanied by two successive processes of "increasing of the sonority" and "opening of the articulatory stricture".