Anatomy of the Vocal Tract

Articulatory System

• The oral and nasal cavities are separated by the hard palate and soft palate
• The three cavities (pharyngeal, nasal, and oral) are known as the vocal tract, involving both articulation and resonance

Articulators

• Include lips, jaw, tongue, pharyngeal wall, and soft palate
• These structures perform movements during speech production

Fixed Structures

• Include hard palate, alveolar ridge, and teeth
• These fixed structures are contacted by articulators during speech production

Oral Cavity

• Comprises muscle, mucus membrane, and fat, covered with skin
• Muscles of the lips provide a great deal of mobility, flexibility, and speed of motion
• Important for chewing, keeping food and liquids inside the mouth

Teeth

• Adults have 32 teeth, which are immovable articulators
• Important for biting, chewing food, cutting, and speech production
• Form connections with the tongue to produce sounds and channel air flow
• Occlusion refers to the dental arches and positioning of teeth
• Malocclusion refers to problems in upper or lower dental arches and positioning

Hard Palate

• A complex bony structure comprising the roof of the oral cavity and the floor of the nasal cavity
• Serves as a barrier between the two cavities, preventing food, air, and sound waves from escaping

Alveolar Ridge

• The point of contact of the tongue for producing many sounds

Soft Palate

• Posterior to the hard palate, containing no bones, and made primarily of muscle
• Also known as the velum, which allows it to move
• The velum hangs down into the pharynx at rest
• Velopharyngeal port is the passageway between the velum and the posterior pharyngeal wall
• When open, air and sound waves move freely through the nasal cavities
• When closed, food, air, and sound waves are prevented from entering the nasal cavities

Tongue

• Has a great degree of flexibility and speed in movements
• Important for chewing, swallowing, and speaking
• Modifies the shape and resonance characteristics of the oral cavity
• Reaches adult size by age 16
• Tongue movements include horizontal (forward-backward), vertical (upward-downward), and concave-convex shapes in relation to the palate

Pharyngeal Cavity

• A long hollow tube made of muscle and connective tissue
• Runs behind the oral and nasal cavities and behind the larynx
• Plays a crucial role in many functions, including swallowing, respiration, and speech
• Important for resonance in speech

Nasal Cavities

• Formed by fusions of bones of the skull
• Divided into two cavities by the nasal septum
• Lined with small hairs to filter inhaled air
• Important for resonating nasal sounds

Voicing

• Consonants can be described as voiced or voiceless
• Voiced sounds are produced with vocal fold vibration
• Voiceless sounds are produced without vocal fold vibration
• Examples: /bay/-/pay/, /van/-/fan/, /dip/-/tip/
• Cognates are phonemes that differ only in voicing

Vowels

• Articulation can be described with respect to tongue position and lip position
• Tongue position is specified along two dimensions: front-back, low-high
• All vowels are voiced
• Vowels can be placed in a format called the vowel quadrilateral
• Vertical plane: low-high
• Horizontal plane: front-back
• Back vowels are produced with lip rounding (who’d, hood)
• Front vowels are not produced with lip rounding (heat, hate)

Explore the anatomy of the vocal tract, including the pharyngeal, nasal, and oral cavities. Learn about the articulatory system and the structures involved in articulation and resonance.