Vowel constrictions are recoverable from formants

Area of Science:

• Acoustic Phonetics
• Speech Perception
• Articulatory Phonetics

Background:

• The precise spatial details of the vocal tract's area function are not directly computable from speech signals.
• Theories of speech perception differ on whether articulatory information is recoverable from acoustic signals.
• Existing theories lack firm evidence for or against the extractability of distinctive articulatory information.

Purpose of the Study:

• To investigate if linguistically significant articulatory information (constriction location, degree, rounding) for vowels is present in the speech signal.
• To determine if this articulatory information is recoverable from formant parameters.
• To assess the accuracy of recovering vowel constriction information from acoustic data.

Main Methods:

• Combined perturbation theory and linear prediction to analyze vowel constrictions.
• Estimated distinctive constriction information from speech signals for ten American English vowels.
• Compared acoustic-derived information with X-ray microbeam articulatory data from 39 speakers.

Main Results:

• Developed a novel technique using formant frequencies and amplitudes for articulatory information recovery.
• This method does not rely on principal components analysis of articulatory data.
• Results demonstrate that distinctive articulatory information for vowels can be recovered from the acoustic signal.

Conclusions:

• Distinctive articulatory information, crucial for understanding speech production and perception, is recoverable from the acoustic signal.
• The developed technique offers a new approach to acoustic-phonetic analysis.
• This finding has implications for speech perception models and speech technology.