The Swahili region was expanded due to several factors, including historical, cultural, geographical and commercial ones. This resulted in a variety of dialects of Swahili speakers. The aspect of phonetic differences is very important among Swahili dialects, so this research is focusing on the vocal differences between the dialects of Kiunguja and Kibara. The researcher collected the material of this research from two ways. First: through blogging, where the researcher collected his material through direct dialogue with the people of the two dialects. Second: through collecting words that have vocal differences from the lexicons “Kamusi ya Kiswahili Sanifu" and “Kamusi la Kiswahili Fasaha". This research is focusing on the vocal differences between the dialects of Kiunguja and Kibara, with the aim of determining the different usage of the silent, sounds and semi-sounds. By this way, the research contributes to the Library of Swahili Linguistics and its dialects. The researcher used a comparative linguistics approach. The research is divided into three sections that are mentioned in the introduction on the variety of the Swahili language. The first section outlines the phenomenon of the difference of the silent letters, the phenomenon of replacing some of the silent letters in the center and the beginning of the word, the phenomenon of inserting the silent in the center and the beginning of the word, then the phenomenon of deleting the silent in the center, and finally the phenomenon of replacing a silent with a vocal letter. The same thing was presented by the researcher in the phenomenon of replacing the sounds and their combination, deleting and prolonging them at the beginning, center and end of the words. The third topic focused on the issue of semi-sound differences in words and its location in the word. At the end of the research, the researcher presented the research findings and recommendations. Then the research supplements and references relied on.