The purpose of this study is to characterize the intonational realizations of vocatives in comparison with those of appositives in English statements and questions, and to compare the realizations produced by English native speakers with those of Korean students. Unlike Pierrehumbert(1980), in which the tag expressions do not have pitch accents, Beckman & Pierrehumbert(1986) proposed that the vocatives have a special status in tonal alignment and duration and that they form an independent phrase with pitch accent. Our results reinforce Beckman & Pierrehumbert(1986): both English native speakers and Korean students realize the vocatives in terms of rising tone, and the appositives in terms of both falling tone in statements and rising tone in questions. Moreover, they pronounced the nouns before vocatives longer than those before appositives. However, native speakers impose the low phrase tone before vocatives in statements and the high tone in questions; whereas, Korean students either put the low phrase tone on pitch contours of both statements and questions, or tend to pause before vocatives, thereby constituting an intonational phrase.