This study is a description of the linguistic differences between three Persian dialects. The underlying aim of the study is to provide the linguistic facts necessary to evaluate the implications of divergence between the dialects for students of Persian. It would appear that if students experience difficulty in adjusting from one dialect to another, a revision of teaching policies would be in order. This revision would provide either instruction in three separate dialects, or some sort of "core" Persian to which the features that distinguish one dialect from another could be added. The study looks at both the Standard Persian spoken in Iran, Afghanistan, and the Tajik Soviet Socialist Republic, and at three colloquial dialects, Tehrani, Kabuli, and Varzobi. This is due to the fact that the standard languages are restricted to the sociolects of writing and formal speech, and a description of them alone would not include varieties used in ordinary conversation. The following aspects of the dialects are described: (1) phonology, specifically vowels, consonants, semivowels, and stress; (2) morphology, specifically nominal affixes, pronouns, demonstratives and indefinites, numerals, and verbs; and (3) lexicon. (CLK)