This article evaluates the "Frames, then Content" hypothesis for speech acquisition, which sees babbling as a direct result of producing syllabic "frames" by rhythmic mandibular oscillation with little of the "content" seen under mandible-independent control. Analysis of 6,659 utterances of 6 normally developing infants over a 4-6 month period supported a conception of babbling as "Frame Dominance." (Author/DB)