This paper investigates the domain-initial strengthening in English and Hamkyeong Korean, a pitch accent dialect spoken in the northern part of North Korea. Domain-initial strengthening, which refers to the phonetic prominence of the initial positions, has been assumed to be cross-linguistically universal phenomenon due to the contrast preservation of the domain-initial syllables in phonology. The question addressed in the present study is whether the domain-initial strengthening effect is observed at the domain-initial vowels as well as domain-initial consonants. In the experiment, durations of initial-syllable vowels in various prosodic domains were compared with those of second vowels in realword tokens for both languages. Hamkyeong Korean, like English, tuned out to strengthen the domain-initial consonants. With regard to vowel durations, we found no significant prosodic effect in English. On the other hand, Hamkyeong Korean showed significant differences between durations of initial and non-initial vowels in the higher prosodic domains. The findings in the study are theoretically important as they show that the potentially-universal phenomenon of initial strengthening is subject to language specific variations in its implementation.