Dissertation (MA Linguistics)The purpose of the study was to assess the impact of code-switching used in modern taarab to Swahili language in Tanzania. Specifically the study aimed to asses the transformation of language use in taarab since 1990 up to 2015, to investigate the ways code-switching happens in modern taarab and to find out the impacts of code-switching as it is used in modern taarab to Swahili language. The study used a qualitative research approach in data collection and data analysis. The sample size of this study is 35 informants. Data were collected through observation, documentary review and interview. This study is grounded in Communicative Accommodation theory, a theory used to analyse factors and reason of code switching in the society. Analysis of language transformation in taarab music revealed that there are the use of code-switching in modern taarab. Also the study showed that in modern taarab music intersentential switching and intrasentential switching. The use of code switching brought some positive and negative impact to the society. The studies finally conclude by suggesting that the language use in taarab should be observed to avoid language transformation and more research should be conducted on other type of music concerning language use.