M. Tech. Language Practice / South Africa's multilingual ecology requires acquisition of proficiency in several languages if one is to participate effectively in the economic, political, and socio-cultural spheres of the country. The study concentrates on the acquisition of a third language by adult university students in die Departments of Applied Languages, Education and Journalism, which they do as a requirement for their various qualifications. This study investigates the manifestation of Transfer of Cross-Linguistic Influence from the learners' previously-known languages during the acquisition / learning for a third language, Northern Sotho. The study examines errors identified in the language learners' written production of their interlanguage in Northern Sotho L3