The influence of body posture on the acoustic speech signal

Few studies address the influence of postural changes on the vocal mechanism, and where they do so, they most often neglect the acoustic implications. This study tested participants in upright, prone and supine posture and assessed the resulting changes in formant frequencies and F0. Results show that while most formants appear to be subject to compensation strategies by the speaker, F3 differs consistently between body postures. F0 as well rises in nonneutral postures. This work is of relevance to the forensic-phonetic framework, which is reliant on higher formant frequencies in particular to carry out forensic speaker comparison. Further research is needed in order to assess articulatory movement with respect to its acoustic correlates.