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Coarticulation in fluent fingerspelling.
Thomas E Jerde1, John F Soechting, Martha Flanders
1Department of Neuroscience, University of Minnesota, Minneapolis, Minnesota 55455, USA.
Summary
Sign language interpreters exhibit coarticulation in fingerspelling, influencing hand shapes based on surrounding letters. This movement fluency, seen in proximal interphalangeal joints, enhances visual discrimination.
Area of Science:
- Motor control and biomechanics
- Linguistics and communication sciences
- Human-computer interaction
Background:
- Coarticulation in speech demonstrates non-serial motor control.
- Comparable fluency in skeletal motor systems has been less understood.
- Sign language offers a unique model for studying complex movement sequences.
Purpose of the Study:
- To quantify coarticulation in sign language fingerspelling.
- To investigate influences between sequential hand shapes.
- To analyze joint-specific assimilation and dissimilation patterns.
Main Methods:
- Recording 17 joint angles during fingerspelling by sign language interpreters.
- Utilizing discriminant and correlation analyses.
- Categorizing influences as assimilation or dissimilation.
Main Results:
- Substantial evidence of coarticulation found in hand movement sequences.
- Identified both forward and reverse influences across letters.
- Observed dissimilation in index/middle finger PIP joints and assimilation in wrist/thumb joints simultaneously.
Conclusions:
- Sign language fingerspelling displays sophisticated coarticulation, similar to speech.
- Dissimilation in key finger joints may enhance visual letter recognition.
- Parallel control of multiple joints during a serial task is demonstrated.