From the Guidelines
Speech production involves the coordinated effort of multiple muscle groups, including the diaphragm, intercostal muscles, abdominal muscles, laryngeal muscles, and articulatory muscles in the mouth and face. The primary muscles used for speech can be broken down into several categories:
- Respiratory muscles: diaphragm, intercostal muscles, and abdominal muscles, which control breathing and provide airflow 1
- Laryngeal muscles: vocalis, thyroarytenoid, and cricothyroid muscles, which control the vocal folds to produce sound
- Articulatory muscles:
- Tongue muscles (intrinsic and extrinsic)
- Lip muscles (orbicularis oris)
- Soft palate muscles (levator veli palatini)
- Jaw muscles (masseter, temporalis, and pterygoids) These muscle groups work together to shape sounds into recognizable speech, with the tongue playing a particularly important role due to its remarkable dexterity and ability to make precise movements to form different sounds. As noted in the guidelines for adult stroke rehabilitation and recovery, disorders such as dysarthria and apraxia of speech can result from paralysis, weakness, or incoordination of the speech musculature after neurological damage 1.
From the Research
Muscles Used in Speech Formation
The muscles used to form speech include:
- Orbicularis oris muscle, which plays a role in lip shape and movement 2
- Orbicularis oris superior (OOS) and inferior (OOI) muscles of the lips, which are involved in force-generation dynamics of human articulatory muscles 3
- Tongue muscles, which work together to generate movement and shape in speech articulation 3
- Vocal cord muscles, which are affected in spasmodic dysphonia, a neurological voice disorder that impacts speech 4, 5, 6
- Laryngeal muscles, which are targeted with botulinum toxin injections to treat spasmodic dysphonia 4, 5, 6
Specific Muscle Functions
- The orbicularis oris muscle is responsible for lip shaping and movement, with a peripheral and moderately deep implementation being most appropriate for protrusion and rounding 2
- The OOS and OOI muscles have similar characteristics in terms of force-generation dynamics, with a natural frequency of 6.1 Hz and a damping ratio of 0.71 and 0.68, respectively 3
- The vocal cord muscles are affected by spasmodic dysphonia, which can cause involuntary spasms and impact speech quality 4, 5, 6