Does visual speech information affect word segmentation?

We present an experiment in which we explored the extent to which visual speech information affects learners' ability to segment words from a fluent speech stream. Learners were presented with a set of sentences consisting of novel words, in which the only cues to the location of word boundaries were the transitional probabilities between syllables. They were exposed to this language through the auditory modality only, through the visual modality only (where the learners saw the speaker producing the sentences but did not hear anything), or through both the auditory and visual modalities. The learners were successful at segmenting words from the speech stream under all three training conditions. These data suggest that visual speech information has a positive effect on word segmentation performance, at least under some circumstances.