Native speakers of Japanese were asked to repeat 2 and 3-syllable English words, with varying lexical stress placements, spoken by a native speaker of American English. One group of words consisted of unaltered sonorant and semi-sonorant nouns, while the second group contained the same words, but with artificially flattened fundamental frequency (F0) and intensity contours. Speakers' accuracy in producing the prosodic characteristics of the English words was determined acoustically by analyzing the F0 contour, intensity contour, and syllable-duration of their utterances. Production of the correct prosodic characteristics was affected by the number of syllables and place of the lexical accent, as well as by the individual subject's level of familiarity and understanding of the word. Furthermore, the results show that subjects' accuracy was influenced by the prosodic modification of the words.