The two-and three-syllable reduplicative babbling of five French-learning and five English-learning infants (o;5 to i; i) was examined in two ways for intonational differences. The first measure was a categorization into one of five categories (rising, falling, rise-fall, fall-rise, level) by expert listeners. The second was the fundamental frequency (F 0 ) from the early, middle and late portion of each syllable. Both measures showed significant differences between the two language groups. 65 % of the utterances from both groups were classified as either rising of falling. For the French children, these were divided equally into the rising and the falling categories, while 75 % of those utterances for the English children were judged to have falling intonation. Proportions of the other three categories were not significantly different by language environment. In both languages, though, three-syllable utterances were more likely to have a complex contour than two-syllable ones. Analysis of the F 0 patterns confirmed the perceptual assessment. Several aspects of the target languages help explain these intonational differences in prelinguistic babbling. © 1991, Cambridge University Press. All rights reserved.