Patterns of variance in /s/ during normal and glossectomy speech

Area of Science:

• Linguistic research
• Speech production
• Articulatory phonetics

Background:

• Speech production exhibits significant variability in articulatory gestures, even for perceived consistent sounds.
• The /s/ sound has variants (apical and laminal) that may involve different tongue gestures, but this is not well-quantified.

Purpose of the Study:

• To quantify internal tongue motion differences between apical and laminal /s/ allophones in normal speakers.
• To investigate the impact of tongue cancer surgery on these speech gestures compared to controls.

Main Methods:

• Tagged Magnetic Resonance Imaging (MRI) was used to capture midsagittal tongue motion patterns.
• Principal Components Analysis (PCA) identified variability patterns distinguishing subject groups and /s/-types.

Main Results:

• No significant differences in tongue tip or whole-tongue motion were found between apical and laminal controls.
• Apical patients post-tongue cancer surgery displayed uniform, distinct tongue tip motion (no elevation, downward/backward movement).
• These patient movements suggest difficulty maintaining proper tongue-palate proximity.

Conclusions:

• Articulatory differences for apical and laminal /s/ allophones are not supported by observed tongue motion in healthy speakers.
• Tongue cancer surgery significantly impacts tongue tip articulation, leading to a specific, uniform motion pattern in patients.