This paper examines variation found in the usage of English relatives by Korean users and learners of English. Two types of data are analyzed using Varbrul analysis: academic articles written by English major professors and compositions by college students majoring and minoring in English. The results of analyses can be summarized as follows: 1) Korean users and learners of English adopt wh-variants more frequently than Americans for use but less commonly than Britons, 2) Advanced English users generally show the usage pattern of English relatives similar to that of native English speakers conditioned by very similar linguistic constraints, 3) Korean English learners with intermediate proficiency level revealed somewhat different patterns of English relative use from those of native English speakers and advanced Korean English users, 4) Prescriptive grammar taught in middle and high schools is analyzed as exerting significant influence on the pattern of English relative use by Korean users and learners of English. (157)