Intrinsic Laryngeal Muscle Activity During Subvocalization

Area of Science:

• Linguistics
• Neuroscience
• Physiology

Background:

• Subvocalization, the subtle activation of speech muscles during thought or reading, is thought to mediate phonological representations.
• Previous research has not directly measured intrinsic laryngeal muscle (ILM) activity during subvocalization.

Purpose of the Study:

• To directly measure ILM activity during subvocalization.
• To determine the implications of ILM activation for establishing experimental baselines in linguistic research.

Main Methods:

• Two studies involving 45 cisgender women performing silent-silo tasks.
• Fine-wire electromyography to measure ILM activity during rest and subvocalization tasks.
• Surface electromyography for submental, anterior tibialis, and upper trapezius muscles.

Main Results:

• Interrupted time-series analysis and t-tests assessed changes in ILM activity from baseline.
• Individual participants showed statistically significant increases or decreases in ILM activity.
• Most measured muscles (16/21) had negligible effect sizes; only the right cricothyroid showed significant group-level changes.

Conclusions:

• Intrinsic laryngeal muscle responses during subvocalization exhibit variable magnitude and direction.
• Most observed changes are negligible, but individual variations exist.
• Researchers should consider idiosyncratic subvocalization variations when selecting baseline tasks for studies involving linguistic processing.