From a linguistic point of view, when a word from one language enters another language, in order to survive there, it needs to adapt itself to the phonetic, phonological, morphological, syntactic, and semantic principles and patterns of that language. Otherwise, it will be excluded from the lexicon of the host language. In this paper, the writers have examined and analyzed the various types of phonological changes in the lexicon of Pahlavi language or Middle Persian which have resulted in the development of their new forms in modern Iranian languages, such Talysh. A study of the terms in Concise Pahlavi Dictionary by D. N. Mackenzie and their comparison with some of the words collected from oral Talysh utterances produced in Anbaran, a district near the joint frontier of Iran and Azerbaijan, demonstrated that the words shared by the two languages have undergone some changes, such as blending, assimilation, ellipsis, inversion, addition, and some other common phonological processes, in their moving from Pahlavi language and entering Talysh language. Moreover, some terms have entered this language in their original form.