Studies relevance to Mazandarani language shows the speakers tendency to persian language. The method of this research, which is descriptive- analytic, is estimating the amount and the quality of using Mazandarani words among Jouybari speakers (Jouybar is a small town in the center of Mazandaran). The purpose of this study is estimating age as a social factor in using Mazandarani local words by using “Questionnaire for gathering Dialects” prepared by Bahram Farahvashi and Moris swaddesh list. Fifty speakers from five aging groups: the aged(60 to up), adults(40 to 60),the youth(20 to 40), adolescents(10 to 20) and child(2 to 10) are chosen. The research sample is composed of 200 of 1300 dialect words in questionnaire. The results are arranged in three tables. The first table is composed of the words with the highest frequency. The second table is divided to five tables. Each table is set on the basis of all the presented answers and their percentages. In the third table, which is the basis of the analysis, all the words divide to eleven categories (relativeness,animals,food,house,facilities,objects, sentence, infinitives, disease, natural phenomena, organs of body, genitive expressions). The most used words with their percentages are shown in this table. The average of frequency is calculated according to the eleven categories in different ages. These averages are: 1-Total average of eleven categories in using Mazandarani-Jouybari words for 60 to up years old is%83/43, for 40 to 60 is %81/22, for 20 to 40 is %77/68, for 11 to 19 is %44/84 and for 2 to 10 years old is %14/25. On the whole, the received results shows that the most tendencies to using Mazandarani words is among the aged or parents. The number of speakers decreases among adolescents and children. The received results shows the language change from Mazandarani to Persian.
