Do weak syllables count for newborns?

Does the newborn's well-known sensitivity to human speech include awareness of the distinction between strong and weak syllables, as has been shown for older infants and adults? The non-nutritive high-amplitude sucking paradigm was used to investigate whether weak syllables play a role in neonate perceptual representation. Two-day-old French infants were tested on their capacity to discriminate phonetically highly varied words containing syllables with various strong vowels versus the weak, reduced vowel schwa in natural, isolated English words. Twenty infants heard lists of weak-strong and lists of strong words (e.g., belief, control, etc. versus nose, dream, etc.) and 20 heard lists of weak-strong and strong-strong words (e.g., belief, control, etc. versus volume, rhubarb, etc.). The results show that weak-strong words were reliably distinguished from strong words, but not from strong-strong words. Taken together, the findings indicate that a weak, reduced vowel is equivalent to a strong, full vowel to the extent that both count as syllabic nuclei. Moreover, this global equivalence in terms of number of syllabic constituents apparently over-rules the more local acoustic difference between strong and weak vowels. The role of syllabic/vocalic information in neonate representation is discussed.