As opposed to speech-only tone analysis, Mixdorff and Burnham (2005, 2004) explored another avenue. He believed that tone patterns of Thai could be partly determined using visual cues. An experiment was done by tracking movement points on speaker faces with respect to uttered words in various tones. Results, however, showed that articulatory gestures were primarily a function of the word being uttered and only secondarily a function of tones.