Speech rate reduction and "nasality" in normal speakers.

Area of Science:

• Speech Science
• Acoustic Phonetics
• Speech Motor Control

Background:

• Understanding the relationship between speech production mechanics and perceptual qualities is crucial.
• Nasal/voice accelerometry offers an objective measure of laryngeal and nasal airflow.
• Investigating the impact of speaking rate on these measures is essential for clinical and research applications.

Purpose of the Study:

• To investigate the effects of reduced speech rate on nasal/voice accelerometric measures.
• To compare these objective measures with subjective nasality ratings from experienced listeners.
• To determine the correlation between acoustic/mechanical speech parameters and perceived nasality.

Main Methods:

• Adult participants produced various speech stimuli (sentences, syllable trains) at different speaking rates (normal, reduced, computer-paced).
• Nasal/voice accelerometric data were collected during speech production.
• Listeners provided nasality ratings for the recorded speech samples.

Main Results:

• Nasal/voice accelerometric measures showed significant effects related to speech stimulus but not speaking rate.
• Listener nasality ratings exhibited small but significant effects for both stimulus and speaking rate.
• A poor correlation was found between the objective accelerometric measures and the subjective nasality ratings.

Conclusions:

• Speaking rate does not appear to significantly alter nasal/voice accelerometric output in normal speakers.
• Subjective perception of nasality is influenced by speaking rate, though weakly.
• Nasal/voice accelerometry may not reliably reflect perceived nasality, especially across different speaking rates.