Influences of pellet markers on speech production behavior: Acoustical and perceptual measures

Abstract

Peri- and intraoral devices are often used to obtain measurements concerning articulator motions and placements. Surprisingly, there are few formal evaluations of the potential influence of these devices on speech production behavior. In particular, the potential effects of lingual pellets or coils used in x-ray or electromagnetic studies of tongue motion have never been evaluated formally, even though a large x-ray database exists and electromagnetic systems are commercially available. The x-ray microbeam database [Westbury, J. "X-ray Microbeam Speech Production Database User's Handbook, version 1" (1994)] includes several utterances produced with pellets-off and -on, which allowed us to evaluate effects of pellets for the utterance, She had your dark suit in greasy wash water all year, using acoustic and perceptual measures. Overall, there were no acoustic or perceptual measures that showed consistent effects of pellets across speakers, but certain effects were consistent either within a given speaker or in direction across a subgroup of the speakers. The results are discussed in terms of the general goodness of the assumption that point parameterization of lingual motion does not interfere with normal articulatory behaviors. A brief screening procedure is suggested to protect articulatory kinematic experiments from those individuals who may show consistent effects of having devices placed on perioral structures.

Proceedings of the 5th Workshop on Speech and Language Processing for Assistive Technologies

“…Prior to the experiment, each subject participated in a three-minute training session (on how to use the SSI), which also helped them adapt to the oral sensors. Previous studies have shown those sensors do not significantly affect their speech output after a short practice (Katz et al, 2006;Weismer and Bunton, 1999).…”

Influence of a Standard Electropalatography Artificial Palate Upon Articulation

“…These audio signals were digitised at a rate of 20 kHz, using 16 bits of quantisation. Measures employed previously in articulatory perturbation studies were used to determine the effect of the artificial palate upon speech production [17,19] . The measures included were as follows:…”

“…The listeners were asked to complete a rating of the speech stimuli using a procedure similar to that of Weismer and Bunton [17] . The raters were instructed 'You will hear a series of repetitions of the phrase, say __ again ; please listen carefully and decide if you think the speaker is wearing an artificial palate or not, then place a tick in the appropriate column (yes/no) beside the phrase number'.…”

“…Only the phrases with 80% inter-judge agreement (i.e. in which 4 out of 5 of the listeners responded similarly) were included in the analysis of results [17] . These were termed 'consistently' judged and amounted to 253 of the total 405 productions (63% of the total number of phrase recordings).…”

“…Weismer and Bunton [17] stated that 'the demonstrated influence of pseudopalates on articulatory behaviour makes it difficult to evaluate the generalizability of findings from electropalatographic studies of speech production' (p. 2882). This seems a particularly pertinent issue as, in recent times, EPG has been used to make inferences about underlying speech motor control processes in healthy and neurologically impaired speakers [18] .…”