There are different ways to classify derivational affixes. This article investigates Persian derivational affixes according to the classification presented by Beard (2001). His classification is different from others in considering the affixes’ features, semantic functions, and grammatical changes. The problems and the limitations of this classification in Persian are also discussed here. Moreover, based on Beard’s theory on derivational head (which suggests that if affixes are lexical items selected for phrase structures, they should be served as heads), the derivational head in Persian is discussed together with the inadequacy of this theory. To overcome some of these shortcomings, the present study suggests at least three additional classes of derivation: Archi derivation (including several classes), semantic derivation (changing just the function) and referent derivation (changing just the reference)
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