This paper deals with the impact of the Raya Dialect (RD) variations and the influence of Amharic on the Tigrinya variety used as a medium of instruction (MOI), particularly in Alamata primary schools. The study is mainly concerned with the description of the linguistic disparities between the RD and Standard Tigrinya (ST) and analysis of linguistic interference of the RD and Amharic into the ST. It is also aimed at pointing out the impacts of the linguistic disparities between the two varieties and the influence of Amharic on the LOI, at assessing the attitudes of the students of Alamata primary schools towards ST as LOI, and at suggesting some measures which can possibly solve or reduce the impacts. In order to achieve these objectives, a questionnaire, interview, a writing test and personal classroom observations have been used as the main data collection instruments.