In this paper the production of English liquids /l/ and /r/ by one native speaker of American English and two native speakers of Korean with nearly the same degrees of experience and proficiency with American English was studied, and data obtained by analyzing spectrograms provide the basis for comparing a group of university students and a group of Korean teachers of foreign languages. The two groups were given a test for listening comprehension at different times with the same sentences including words with /l/ and /r/. The findings are that the finality of English liquids proves to cause both groups common problems with articulation because of their acoustic similarity and that final /l/ and /r/ should be paid special attention to in terms of perception as well as production.