Internal speech is faster than external speech: Evidence for feedback-based temporal control

Area of Science:

• Speech production and motor control
• Auditory and speech perception
• Cognitive neuroscience

Background:

• A prominent model suggests sensory feedback is crucial for controlling speech rate and articulatory timing.
• This model implies that speech produced without sensory feedback (internal speech) may differ in timing from externally produced speech.

Purpose of the Study:

• To investigate the role of sensory feedback in temporal speech control.
• To compare speech durations in conditions with and without sensory feedback.

Main Methods:

• An experiment compared phrase durations in external speech (with sensory feedback) versus internal speech (without sensory feedback).
• Phrase lengths were manipulated using one to three disyllabic nouns within a target phrase.
• An inferred duration method estimated internal speech phrase durations.

Main Results:

• Internal speech was found to be significantly faster than external speech.
• A noticeable slowdown occurred when transitioning between internal and external speech production modes.

Conclusions:

• The findings support the hypothesis that speakers utilize sensory feedback for temporal speech control.
• The study highlights a production cost associated with switching between internal and external speech modes.