The objective of this Korean education basic research is the examination of Korean language aspects of foreign non-native, marriage immigrant women living in Korea whose L1s are Japanese and Tagalog(Filipino) mothers. The interlanguage aspects of the participants is analyzed using Mean Length of Utterance(MLU), particularly MLUw and MLUm. The results of the analysis showed a difference in MLUm during conversations between mothers and adults, but did not between mothers and children. When comparing MLUm, Japanese mothers were found to use more morphemes than Filipino mothers. This suggests that MLU is influenced depends upon L1 and that a non-native speaker will attempt to match their MLU with an interlocutor’s MLU. In regards to the aspect of interlanguage of marriage immigrant women, it first shows that universal interlanguage is not concerned with L1. This is due to the pro-verb usage of ‘하다’ which appeared equally among native Korean child interlanguage during early phases of language acquisition. This confirms interlanguage’s universality. Secondly, this language shows that language users with a high MLUm do not necessarily utter less interlanguage. Interlanguage is a universal phenomenon unconcerned with L1 regardless of MLU. This research confirms the reliability of MLU as a tool to measure Korean utterance fluency of married immigrant women, but cannot be used to measure the accuracy of those utterances. (Keimyung University)