In 1986, we have studied in the area of the old Izumo clan and the old Iwami clan in Shimane Prefecture for the research, ''Border area between Izumo and Iwami", to find out the diversity in regional dialects. There are two references which are available for this research, namely "LlNGUISTIC ATLAS OF JAPAN" and “LlNGUISTIC ATLAS OF THE FIVE PROVINCE OF WEST JAPAN". From the references, we could find explicit difference among the two areas in the use of the words. The former studies in the references were conducted 25 years prior to our study. The purpose of this study is to compare the changes in the two dialects of the areas from the chronological viewpoint, namely the former study and our study. The types of changes can be classified into the five types. (Type A) There is no explicit difference in the use of words. And 70% of the result in our study falls into this type. (Type B) The use of words in Izumo area affected the ones in Iwami area. (Type C) The use of words affected nearby areas from the core city Izumo. (Type D) The use of words in Iwami area affected the ones in Izumo area. (Type E) New commonly used words were developed and became a wider use in the two areas. It seems that type B and type C are the result of the strong influence by the core city Izumo which has a strong political, economical and cultural power in the areas.