Oh Ahrim This study has investigated the acquisition of eun/neun and i/ka by Japanese and Chinese learners. The appropriateness of eun/neun and i/ ka depends on linguistic contexts, such as particular sentence components in the sentence and prior utterance. Linguistic contexts in which eun/neun is used are genericity, givenness, and contrast. i/ka occurs in contexts such as informational focus, selecting focus, replacing focus, exclusiveness, specificity, confirmation question, rhetoric question and indefinite subject noun. Altogether, 30 L1 Japanese learners of Korean(JKs), 30 L1 Chinese learners of Korean(CKs) and 30 native speakers of Korean(NKs) participated in the study. A Likert-scale was used to review participants’ perceptions and an ANOVA was used for statistical analysis of the results. The results showed that CKs were significantly different from NKs in all of the contexts, while there were significant differences between JKs and NKs in four contexts: genericity, replacing focus, rhetorical question and indefinite subject noun. This indicates that morphological congruency of native language of the learners and target language is one variable that significantly influences second language acquisition.