Non-native speakers from five different language backgrounds (Chinese, Hausa, Japanese, Persian, and Spanish) and three native American English speakers produced tokens of two-syllable words (complete), three-syllable words (completion), and four-syllable words (competition) in isolation and in sentence context. Vowel duration, a correlate of stress, was measured in the first two syllables in words from spectrograms. The Americans used very short vowels in the reduced syllables and shortened stressed vowels in suffixed words and in sentence context. The primary difficulties of the non-native speakers were vowel reduction in unstressed syllables and the stress patterns of four-syllable words.