Vitamin B12 Deficiency: This condition is a common cause of numbness or tingling sensations in the tongue and other parts of the body. Vitamin B12 plays a crucial role in the production of myelin, the fatty substance that surrounds and protects nerve fibers, facilitating the transmission of nerve impulses.

Dental or Oral Conditions: Conditions such as a dental abscess, gum disease, or trauma to the tongue can cause numbness. The proximity of dental structures to the tongue and the rich innervation of the oral cavity make these conditions plausible causes.
Medication Side Effects: Certain medications, including some antidepressants, antihistamines, and blood pressure medications, can cause numbness or tingling as a side effect. The mechanism often involves alteration of nerve function or electrolyte imbalance.
Hypothyroidism: This condition can lead to neurological symptoms, including numbness or tingling in the tongue and extremities, due to the metabolic effects of thyroid hormones on nerve function and myelin production.

Multiple Sclerosis (MS): Although less common, MS is an autoimmune disease that affects the brain and spinal cord, leading to a wide range of neurological symptoms, including numbness or tingling in the tongue. Early diagnosis is crucial for effective management.
Stroke or Transient Ischemic Attack (TIA): Sudden onset of tongue numbness, especially when accompanied by other neurological deficits such as facial weakness or difficulty speaking, could indicate a stroke or TIA. Prompt recognition and treatment are critical to prevent permanent damage.
Diabetic Neuropathy: In people with diabetes, high blood sugar levels over time can damage nerves, leading to numbness, tingling, or pain in various parts of the body, including the tongue.

Sjögren's Syndrome: An autoimmune disorder that primarily affects the glands that produce tears and saliva, but can also cause neurological symptoms, including numbness or tingling in the tongue.
Sarcoidosis: A condition characterized by the growth of granulomas (inflammatory cells) in various parts of the body, which can affect the nerves and cause numbness or tingling sensations.
Peripheral Neuropathy due to Other Causes: Such as amyloidosis, certain infections (e.g., Lyme disease, HIV), or exposure to toxins (e.g., heavy metals), which can all lead to nerve damage and symptoms like tongue numbness.