Producing speech with natural prosodic patterns is an ongoing challenge
for users of electrolaryngeal (EL) speech. This study describes speech
produced using a method currently in development, wherein a prosodic
pattern is derived from skin surface electromyographical (sEMG) signals
recorded from under the chin (submental surface).
Eight laryngectomees
who currently use a TruTone EL as their primary or backup mode of speech
provided samples of EL speech in two modes: conventional thumb-pressure
pitch-modulated control (represented by the TruTone EL; Griffin Laboratories,
CA, U.S.A.) and sEMG-based pitch-modulated control (EMG-EL). Ratings
of perceived naturalness were obtained from ten listeners unfamiliar
with EL speech.
Listener ratings indicated that five speakers produced equally
natural speech using both devices, and three produced significantly
more natural speech using the EMG-EL than the TruTone EL. Mean fundamental
frequency (f0) was similar within speakers for both modes; however,
mean f0 range and standard deviation were significantly larger for
the EMG-EL than for the TruTone EL, despite both devices having similar
potential f0 range. This study showed that the EMG-EL provides an intuitive
means of controlling f0-based prosodic patterns that are more natural-sounding
than push-button control for some EL users.