In this research, it has been attempted to determine the social role of two languages, Persian and Mazandarani languages ​​in Qaemshahr and their influence on young people on the use of these linguistic species. In societies with more than one language, we see the collision of languages ​​in various forms. In other words, some consequences of this collision of language cause the loss of the importance of local language and dialects. This loosing of the importance is much influenced development of various industrial organizations in recent years. Technology and communication has led to the influx of native speakers into official and authentic languages. This is an important factor in undermining the status of local languages ​​and a threat to their survival. Mazandarani is one of the regional languages ​​in our country, and its application has been reducing in years to come. The purpose of this research is to study the position and situation of Persian language and its application among youth in Qaemshahr, Iran. This town is an industrial city, and with industrial development, youth's employment in various industries, education, and urbanization are the vital factors in use of Persian language ​​in urban areas and in different situations. In general, it must be clarified/noted the education media is emphasizing on Persian in technology and engineering. The grasp of language is more in lower age groups than older people, and among women is more than men and among urban people is more than rural people. In general, the research findings indicate the erosion and gradual deterioration of the Mazandarani dialect in different areas of the region is increasing. تفاصيل المقالة