This research work investigated the similarity between two languages in contact: Mupun and the Miship languages of Pankshin Local Government Area of Plateau State. The data for this study were collected through the aid of oral interviews and recorded speeches of the informants. The results were analyzed in accordance with the framework found suitable for this study, which is the Variation Theory of Poplack (1993).The major findings of the research work revealed that these two languages, Mupun and Miship have similar lexical items, tones and meanings, hence, the conclusion by the researcher that they are the same language. This research work will be of help to people that are interested in the study of sociolinguistics, particularly language contact.