A longitudinal study of two Korean who returned to Korea after living in the U.S. for two years shows how English attrition can affect their active vocabulary and use of functional categories. A story-telling task was used to collect data from these children for more than three years. The pace, the selective nature, and the pattern of change involving the attrition process were examined. The results show that the lexical diversity of both children decreased consistently over three years since their return to Korea while the accuracy of functional category use declined only in the younger sisters data, with IP affected earlier than DP. The different attrition patterns of lexical diversity and functional categories suggest that language attrition may be a complex process exposing diverse changing patterns of selective linguistic aspects occurring at a distinct pace.