"Pitch" accent in alaryngeal speech

Contemporary review: Impact of primary neopharyngoplasty on acoustic characteristics of alaryngeal tracheoesophageal voice

The physiology of the vibratory mechanism in alaryngeal tracheoesophageal speech depends on several factors. The structure and resulting function of the neoglottis (or neopharynx) varies from patient to patient depending on the individual details of the surgical procedure performed, as well as the patient's anatomy. In general, the vibratory segment is a blending of the pharyngeal constrictor muscles, cricopharyngeus, and upper circular fibers of the esophagus. Limited ability to visualize dynamically these three-dimensional structures during rapid events of voice and speech production impedes complete understanding of the vibratory function of the neopharynx. Acoustic studies have elucidated some general characteristics of the pharyngoesophagus and neoglottic vibratory mechanism in the laryngectomized population. A critical degree of tonicity is necessary for apposition of mucosal surfaces in the production of tracheoesophageal voice. Deficiencies in the vibratory segment can usually be managed with various surgical procedures (neopharyngoplasty), resulting in reduced intraesophageal pressure and corresponding increase in fluent, intelligible, effortless speech. The acoustic measures, when correlated with neopharyngoplasty variables, produce many significant associations. Some of them are paramount and deserve further attention.

Acoustic markers of syllabic stress in Spanish excellent oesophageal speakers

The purpose of this investigation is to explore the use by Spanish excellent oesophageal speakers of acoustic cues to mark syllabic stress. The speech material has consisted of five pairs of disyllabic words which only differed in stress position. Total 44 oesophageal and 9 laryngeal speakers were recorded and a computerised designed ad hoc perceptual test was run in order to assess the accurate realisation of stress. The items produced by eight excellent oesophageal speakers with highest accuracy levels in the perception experiment were analysed acoustically with Praat, to be compared with the laryngeal control group. Measures of duration, fundamental frequency, spectral balance and overall intensity were taken for each target vowel and syllable. Results revealed that Spanish excellent oesophageal speakers were able to retain appropriate acoustic relations between stressed and unstressed syllables. Although spectral balance revealed as a strong cue for syllabic stress in the two voicing modes, a different hierarchy of acoustic cues in each voicing mode was found.

Acoustic markers of prosodic boundaries in Spanish spontaneous alaryngeal speech

Prosodic information aids segmentation of the continuous speech signal and thereby facilitates auditory speech processing. Durational and pitch variations are prosodic cues especially necessary to convey prosodic boundaries, but alaryngeal speakers have inconsistent control over acoustic parameters such as F0 and duration, being as a result noisy and less intelligible than normal speech. This case study has investigated whether one Spanish alaryngeal speaker proficient in both oesophageal and tracheoesophageal speech modes used the same acoustic cues for prosodic boundaries in both types of voicing. Pre-boundary lengthening, F0-excursions and pausing (number of pauses and position) were measured in spontaneous speech samples, using Praat. The acoustic analysis has revealed that the subject has relied on a different combination of cues in each type of voicing to convey the presence of prosodic boundaries.

Prosodic boundaries in alaryngeal speech

Alaryngeal speakers (speakers in whom the larynx has been removed) have inconsistent control over acoustic parameters such as F(0) and duration. This study investigated whether proficient tracheoesophageal and oesophageal speakers consistently convey phrase boundaries. It was further investigated if these alaryngeal speakers used the same hierarchy of acoustic boundary cues that is found in normal speakers. A perception experiment revealed that listeners identified prosodic boundaries less accurately in oesophageal speakers. Acoustic analyses showed that laryngeal speakers used pre-boundary lengthening and pitch movements at phrase boundaries, as expected. Tracheoesophageal speakers used pre-boundary-lengthening and pauses and oesophageal speakers used pauses to convey phrase boundaries. Two oesophageal speakers also paused inappropriately, within phrases. Although these two speakers differentiated between air-injection and prosodic pauses, listeners were unable to tell the two types of pauses apart. Alaryngeal speakers might benefit from therapy that specifically teaches them how to optimize their prosodic abilities.