In five experiments, we tested segmentation of word forms from natural speech materials by 8-month-old monolingual infants who are acquiring Canadian French or Canadian English. These two languages belong to different rhythm classes; Canadian French is syllable-timed and Canada English is stress-timed. Findings of Experiments 1, 2, and 3 show that 8-month-olds acquiring either Canadian French or Canadian English can segment bi-syllable words in their native language. Thus, word segmentation is not inherently more difficult in a syllable-timed compared to a stress-timed language. Experiment 4 shows that Canadian French-learning infants can segment words in European French. Experiment 5 shows that neither Canadian French- nor Canadian English-learning infants can segment two syllable words in the other language. Thus, segmentation abilities of 8-month-olds acquiring either a stress-timed or syllable-timed language are language specific. (Contains 3 tables, 4 figures and 5 footnotes.)