Feedback Mechanisms in Speech Production

Servomechanism

Automatic system using error-sensing feedback to adjust actions

Negative Feedback

Diminishes error, stabilizes system

Positive Feedback

Amplifies changes, leads to instability

Auditory Feedback

Type of external feedback

Comes from air/bone conduction

Shows limited but important roles in refining speech targets and error monitoring due to its slowness

Manipulations:

• Delayed Auditory Feedback

• Frequency Altered Feedback

• Amplitude Changes (Lombard Effect)

• Filtering frequencies

Tactile Feedback

Type of external feedback

Touch sensations from articulators and air pressure

Limited role in fluent speakers who rely on learned motor templates

Measured with:

• Esthesiometers (two point discrimination)

• Oral Stereognosis

• Nerve blocks

Proprioceptive Feedback

Information from joints, tendons, muscles

Fast feedback; good for rapid articulation

Limited impact on well-learned speech patterns

Internal Feedback

Hypothetical system delivering brain-based information about motor commands before physical execution

Faster than other feedback

Supported by neural pathways between neural areas and cerebellum (No direct evidence)