Why is the tongue so important?

The tongue plays a critical role in several vital physiological functions, and its importance is well-documented in scientific literature across fields such as anatomy, neurology, speech-language pathology, and sleep medicine. With my academic background, I am always concerned that therapies are scientifically consolidated before I start applying them in my clinical practice. Here’s an evidence-based summary of why the tongue is so important, organized by function and supported by scientific research:

1. Breathing and Airway Maintenance

• The tongue helps maintain airway patency, especially during sleep. Improper tongue posture (e.g., a low or retracted tongue) can contribute to airway collapse and obstructive sleep apnea (OSA).
• Scientific evidence:
  • Isono et al., 1997 (Am J Respir Crit Care Med) demonstrated that tongue positioning significantly affects the collapsibility of the upper airway during sleep.
  • Guilleminault et al., 2016 (J Clin Sleep Med) highlighted the tongue’s role in pediatric OSA and emphasized the importance of myofunctional therapy for strengthening orofacial muscles, including the tongue.

2. Swallowing and Digestion

• The tongue initiates swallowing by moving the bolus of food to the oropharynx.
• It also helps prevent aspiration by coordinating with other muscles during the pharyngeal phase of swallowing.
• Scientific evidence:
  • Logemann, 1998 (Evaluation and Treatment of Swallowing Disorders) describes the tongue’s central role in the oral and pharyngeal stages of swallowing.
  • Electromyography studies (e.g., Hirano et al., 2012, Dysphagia) show tongue muscle activity is crucial for effective and safe swallowing.

3. Speech and Communication

• The tongue is essential for articulation of consonants and vowels.
• It works in coordination with the lips, teeth, and palate to produce intelligible speech.
• Scientific evidence:
  • Kent & Read, 2002 (The Acoustic Analysis of Speech) show how tongue positioning and movement shape the acoustic properties of speech sounds.
  • Functional MRI studies (e.g., Grabski et al., 2012, J Speech Lang Hear Res) map specific tongue movements associated with phoneme production.

4. Facial and Dental Development

• Proper tongue posture (resting against the palate) influences craniofacial growth and dental arch formation.
• A low tongue posture may contribute to malocclusion, narrow palate, and even long face syndrome.
• Scientific evidence:
  • Harvold et al., 1973 (Am J Orthod) showed in primate models that oral postural changes (like low tongue posture) lead to malocclusion and altered facial growth.
  • Proffit et al., 2018 (Contemporary Orthodontics) includes evidence that tongue posture and function influence jaw development.

5. Taste and Oral Sensation

• The tongue contains taste buds (especially on the anterior and posterior portions) and contributes to gustatory processing.
• It is also rich in mechanoreceptors and nociceptors, helping detect texture, temperature, and pain.
• Scientific evidence:
  • Chaudhari & Roper, 2010 (Annu Rev Physiol) describe the physiology of taste buds and how the tongue communicates taste signals via cranial nerves.
  • Bradley, 2000 (Physiology & Behavior) explains sensory innervation and its role in food selection and safety.

6. Neurological Integration

• The tongue is innervated by multiple cranial nerves: hypoglossal (XII) for motor function, and trigeminal (V), facial (VII), glossopharyngeal (IX), and vagus (X) for sensory function.
• Its movements require complex neural coordination, making it a sensitive marker of neurological integrity (e.g., in stroke or ALS).
• Scientific evidence:
  • Kahrilas et al., 1992 (Gastroenterology) explored how brainstem nuclei control coordinated tongue and pharyngeal function in swallowing.
  • Tongue strength and function have been used as clinical indicators in neurological disorders (Ney et al., 2009, Am J Speech Lang Pathol).