Recent investigations with English-learning infants have shown that the rhythmic properties of English influence how infants segment fluent speech. In particular, 7.5-month-old infants have been shown to extract bisyllabic words that conform to the predominant strong/weak stress pattern of English but not weak/strong words. The present series of studies examined whether English-learning 7.5-month-olds’ segmentation abilities are limited to extracting strong/weak bisyllables or whether they are able to segment longer strings, such as trisyllables (strong/weak/strong). The results indicated that infants can segment trisyllabic words from fluent speech but only when the first syllable receives primary stress (e.g., cantaloupe). When primary stress falls on the last syllable (e.g., cavalier), infants segment only the final stressed syllables. Overall, the findings suggest that 7.5-month-old English-learning infants are able to segment longer strings, and that they use stress as a major cue in segmentation. En...