Voice Source Change During Fundamental Frequency Variation

Prosody refers to certain properties of the speech signal including audible changes in pitch, loudness, and syllable length. The acoustic manifestation of prosody is typically measured in terms of fundamental frequency (f0), amplitude and duration. These three cues have formed the basis for extensive studies of prosody in natural speech. The present work seeks to go beyond this level of representation and to examine additional factors that arise as a result of the underlying production mechanism. For example, intonation is studied with reference to the f0 contour. However, to change f0 requires changes in the laryngeal configuration that results in glottal flow parameter changes. These glottal changes may serve as important psychoacoustic markers in addition to (or in conjunction with) the f0 targets. The present work examines changes in open quotient with f0 in connected speech using electroglottogram and volume velocity at the lips signals. This preliminary study suggests that individual differences may exist in terms of glottal changes for a particular f0 variation.