The impact of head and body postures on the acoustic speech signal
This dissertation is aimed at investigating the impact of postural changes within speakers on the acoustic speech signal to complement research on articulatory changes under the same conditions. The research is therefore relevant for forensic phonetics, where quantifying within-speaker variation is vital for the accuracy of speaker comparison. To this end, two acoustic studies were carried out to quantify the influence of five head positions and three body orientations on the acoustic speech signal. Results show that there is a consistent change in the third formant, a change which was most evident in the body orientation measurements, and to a lesser extent in the head position data. Analysis of the results with respect to compensation strategies indicates that speakers employ different strategies to compensate for these perturbations to their vocal tract. Some speakers did not exhibit large differences in their speech signal, while others appeared to compensate much less. Across all speakers, the effect was much stronger in what were deemed âless naturalâ, postures. That is, speakers were apparently less able to predict and compensate for the impact of prone body orientation on their speech than for
Flory, Yvonne
Acoustic phonetics ; Body postures ; Articulatory phonetics ; Forensic phonetics
The impact of head and body postures on the acoustic speech signal. This dissertation is aimed at investigating the impact of postural changes within speakers on the acoustic speech signal to complement research on articulatory changes under the same conditions. The research is therefore relevant for forensic phonetics, where quantifying within-speaker variation is vital for the accuracy of speaker comparison. To this end, two acoustic studies were carried out to quantify the influence of five head positions and three body orientations on the acoustic speech signal. Results show that there is a consistent change in the third formant, a change which was most evident in the body orientation measurements, and to a lesser extent in the head position data. Analysis of the results with respect to compensation strategies indicates that speakers employ different strategies to compensate for these perturbations to their vocal tract. Some speakers did not exhibit large differences in their speech signal, while others appeared to compensate much less. Across all speakers, the effect was much stronger in what were deemed âless naturalâ, postures. That is, speakers were apparently less able to predict and compensate for the impact of prone body orientation on their speech than for
impact head body posture acoustic speech_signal aim investigating impact change within speaker acoustic speech_signal complement articulatory change condition therefore relevant forensic phonetics quantify within speaker variation vital accuracy speaker comparison end acoustic study_carry quantify influence head position body orientation acoustic speech_signal show consistent change third formant change evident body orientation measurement less_extent head position data analysis respect compensation strategy indicate speaker employ different strategy compensate vocal tract speaker exhibit large difference speech_signal others appear compensate much_less across speaker effect much strong deem less natural posture speaker apparently less able predict compensate impact prone body orientation speech