Evidence of a Vocalic Proto-System in the Baboon (Papio papio) Suggests Pre-Hominin Speech Precursors (original) (raw)
Fig 1
Procedure for acoustic analysis and VLS labeling.
(A) Vocalizations in both human and nonhuman primates use the acoustic signal from the vocal folds vibrating at their fundamental frequency (F0). The formant frequencies depend on the configuration of the vocal tract and the lip opening. (B) LPC analysis was used to reveal the formants of each VLS (supplemental information S2 Fig) [28,29]. (C) A Monte Carlo procedure using an n-tube model normalized for the anatomical measures of the baboons’ vocal tracts then served to generate the MAS (shown by the red line). With this normalized MAS reference, any VLSs could be precisely labeled with the IPA vowel symbols [30,31]. (D) The VLSs thus labeled correspond to well-documented articulatory configurations with characteristic tongue positions and lip openings. (A-D) Red-&-black dots indicate the corresponding values for this illustrative grunt vocalization, which is classified as [u].