Chong, Song-Yun. 1999. The Alternation of Liquid Sounds and Syllable Structure. Studies in Modern Grammar 17, 1-14. The erratic alternation of liquid sounds in English sound production is one of the recalcitrant problems for Korean students. This problem is caused by the differences in phonemic distribution between Korean and English languages. I will argue that the differences in phonemic system(other than the range of its distribution) between these languages hardly explicate the reason why in one position the lateral([l]) is replaced by flapping([r]) and in certain other position the flapping is replaced by lateral. This fact, as I have observed, has nothing to do with phonemic inventory (or system) of both languages. This alternation can be recognizable by analyzing the differences of syllable structure along with the syllable constituents between Korean and English. Incidentally, the (re)syllabification setting up by Korean in English sound production is crucial to account for the erroneous substitution of [l] for [r] or vice versa. I am going to use, therefore, the binary branching syllable structure and justify that the erratic alternation can be normalized by relocating the lateral/flapping sounds in syllable constituents.