Language , in the first step, is divided into spoken and written varieties. Both spoken and written language are two sides of the same coin. Both of these media are manifestations of a linguistic system (grammar), but the use of each in communication faces the speaker with a large array of choices, choices that lead to the formation of systematic patterns in the use of grammar. It is not enough to study just the grammatical forms, structures and categories in the format of these patterns. These tell us what choices are available in the grammar, but we also need to understand how these choices are used to create discourse in different situations. The advent of these situations can be sought in linguistic varieties, in registers (varieties that depend on communicative conditions and purposes), and on a smaller scale in dialects (varieties that depend on demographic, regional, or geographical groups). Conversational variety is one of the registers of spoken language, a variety deserving particular attention in its own right. This register is the most common and everyday variety of language. The grammatical features of this register can be identified and described in relation to its functional and structural characteristics. The functional characteristics of the conversational variety are characteristics that distinguish it from other registers. This article deals with grammatical features that are related to the functional characteristics of the conversational variety of the Persian language.