Nasal consonants in esophageal speech

Area of Science:

• Speech Science
• Acoustic Phonetics
• Laryngology

Background:

• Esophageal speech is an alternative alaryngeal speech method for individuals without vocal folds.
• Understanding the acoustic properties of esophageal speech, particularly nasalization, is crucial for improving intelligibility and naturalness.
• Nasal consonants play a key role in speech perception, and their acoustic realization can be altered in alaryngeal speech.

Purpose of the Study:

• To quantify the degree of nasalization in nasal consonants produced by esophageal speakers.
• To investigate the influence of word position on the nasal resonance of esophageal speech.
• To correlate acoustic measurements with the perceived nasal quality of speech.

Main Methods:

• Acoustic analysis of utterances from three esophageal speakers.
• Measurement of nasalization using the ratio of nasal accelerometer signal amplitude to air-borne microphone signal amplitude.
• Systematic variation of word position (initial vs. final) for nasal consonants.

Main Results:

• The degree of nasal resonance was significantly dependent on the word position of nasal consonants.
• Higher nasal resonance values were observed for word-final nasal consonants compared to word-initial ones.
• Acoustic data revealed distinct patterns of nasalization related to temporal factors following air injection.

Conclusions:

• Word position is a critical factor influencing nasal consonant production in esophageal speech.
• Esophageal speakers exhibit increased nasal resonance in word-final positions, potentially impacting speech intelligibility.
• Objective acoustic measures provide valuable insights into the phonetic characteristics of alaryngeal speech.