This paper investigates previous theories on English focus realization and attempts to find out the overall acoustic characteristics of English focus. It has been argued in previous studies that English focus can be defined as a new information that is not recoverable from the context (Halliday 1967), a complementary element of presupposition (Jackendoff 1972), and what is predicated about the topic in a sentence (Sgall 1973, Gundel 1974). The phonetic realization of English focus in an utterance has been said to be either L+H*/H*, or falling accent. Yet it is a more or less simplified pattern not based on real data obtained from native speakers of English, and it does not consider the various pragmatic and contextual situations. In our experiments we found that native speakers uttered English focus sentences in different ways according to the different focus structure. Another notable result is that Korean speakers, when provided with the same experimental material, are neither able to distinguish different focus types nor deaccent the elements that are not focused in an utterance.