More and more learners of English from the Expanding Circle are travelling to Outer Circle contexts to learn English or to improve their English proficiency. This is also the case for some Korean families who moved to Potchefstroom, South Africa. This phenomenon poses challenges in terms of assessment of English proficiency, and emphasizes the increasing "global" reach of English observed by many researchers. A result of this phenomenon is the potential increase in communication difficulties when "world citizens" use English as language of communication. This project aims at exploring these potential communication difficulties. Speech data from Korean speakers of English who live in Potchefstroom, South Africa is used to determine the levels of intelligibility, comprehension and interpretability of Korean English to South African users of English. The speech data is also used to elicit responses from the South African users of English about the perceived levels of English proficiency of the Korean participants. These perceptions are compared with a self-evaluation of English proficiency by the Korean participants. Ultimately, the project endeavours to contribute to a better understanding of perceptions of English proficiency that could lead to solving some of the potential communication difficulties (e.g. intelligibility) in "world Englishes" contexts.