Normal Mechanism for speech includes:

Phonation: the production of sound by the larynx requiring

• Approximation of the vocal folds
• Forced expiration (adequate breath support)
• PASSIVE vibration of free mucosal edge of the vocal fold

Pitch: Is determined by the fundamental frequency of vocal fold vibration

• Dependent on vocal fold length and tension
• Controlled by “pre-phonatory tuning” and auditory feedback

Intensity: Depends on subglottic pressure which is related to

• Expiratory flow
• Glottic and Supraglottic Muscle Tension

Resonance is the modulation of sound through lower, middle, and upper pharyngeal regions. This can be voluntarily modified by movements of the tongue, pharynx and soft palate, as well as by changing the shape of the larynx.

Articulation is the formation of words is accomplished by voluntary movement of the upper aerodigestive tract (i.e., lips, teeth, tongue, palate, etc.) to produce:

• Unvoiced consonants
• Shape phonation into vocalization (speech and song)