Prosodic boundaries in alaryngeal speech

Area of Science:

• Speech and Hearing Sciences
• Linguistics
• Acoustic Phonetics

Background:

• Alaryngeal speakers, who have undergone larynx removal, often exhibit variable control over fundamental frequency (F0) and duration.
• Effective communication relies on prosodic cues, such as phrase boundaries, which can be challenging for alaryngeal speakers to produce consistently.

Purpose of the Study:

• To investigate if proficient tracheoesophageal (TE) and oesophageal (OE) speech speakers consistently signal phrase boundaries.
• To determine if alaryngeal speakers utilize the same hierarchy of acoustic boundary cues as non-alaryngeal speakers.

Main Methods:

• A perception experiment was conducted where listeners identified prosodic boundaries in alaryngeal speech.
• Acoustic analyses examined pre-boundary lengthening, pitch movements, and pauses in tracheoesophageal and oesophageal speech.

Main Results:

• Listeners demonstrated less accurate identification of prosodic boundaries in oesophageal speakers compared to tracheoesophageal speakers.
• Tracheoesophageal speakers utilized pre-boundary lengthening and pauses, while oesophageal speakers primarily used pauses to mark boundaries.
• Two oesophageal speakers produced inappropriate pauses within phrases, which were indistinguishable from prosodic pauses to listeners.

Conclusions:

• Alaryngeal speakers' ability to convey phrase boundaries varies between speech types, with oesophageal speech posing greater challenges for listeners.
• Specific acoustic cues like pre-boundary lengthening and pauses are employed differently by tracheoesophageal and oesophageal speakers.
• Therapeutic interventions focusing on optimizing prosodic abilities may benefit alaryngeal speakers, particularly in mastering pause usage and boundary signaling.