The nature of the visual input that integrates with the audio signal to yield speech processing advantages remains controversial. This study tests the hypothesis that the information extracted for audiovisual integration includes co-occurring suprasegmental dynamic changes in the acoustic and visual signal. English sentences embedded in multi-talker babble noise were presented to native English listeners in audio-only and audiovisual modalities. A significant intelligibility enhancement with the visual analogs congruent to the acoustic amplitude envelopes was observed. These results suggest that dynamic visual modulation provides speech rhythmic information that can be integrated online with the audio signal to enhance speech intelligibility.