The aim of this paper is to find the speech problems of English Laterals by Korean learners and to contribute to the effective pronunciation education with visualizing the pronunciation. In this paper we analyzed 18 words including lateral sounds which were divided into such as: initial, initial consonant cluster, intervocalic, final consonant cluster, and final. To analyse the words we used High speed speech analysis system. We examined acoustic characteristics of English lateral spectrogram by using voice sustained time(ms), FL1, FL2, FL3. Before we started, we had expected that the result would show us that the mother tongue interfere in the final sounds because we have similar sounds in Korea. The results of our experiments showed that initially, voice sustained time showed many more differences between Korean and native pronunciation. Also, it was seen that Korean pronunciation used the syllable structure of the own mother tongue. For instance, in the case of initial consonant cluster CCVC, Koreans often used CC as a syllable and VC as another. This was due to the mother tongue interference. For this reason in the intervocalic and in the final, we saw the differences between Korean and native. Therefore we have to accept the visualized analysis system in the instruction of pronunciation.