Poor speaking tongue may be caused by stroke, Guillain-Barré syndrome, oral ulcers, periodontitis, tongue cancer and other causes. 1. Stroke: acute cerebrovascular embolism leads to ischemic infarction of brain tissue or acute cerebral hemorrhage leads to pressure on brain tissue, etc., resulting in local dysfunction of the brain, and the nerves innervating the tongue muscles such as the hypoglossal nerve function abnormally, and so this symptom appears. 2. Guillain-Barré syndrome: the peripheral nervous system is attacked by the autoimmune system, resulting in damage to the nerves innervating the tongue muscles, such as the hypoglossal nerve, and this symptom occurs. 3. Mouth ulcers: ulcerative lesions on the tongue and oral mucosa, which are painful when the tongue movement stimulates the surface of the ulcer. 4. Periodontitis: Inflammatory lesions of the periodontium caused by bacterial infection and other factors, localized redness, swelling, heat and pain, affecting the movement of the tongue, so this symptom appears. 5. Tongue cancer: malignant hyperplasia of tongue tissue leads to hyperplasia, ulceration and other changes of tongue, so this symptom appears. Poor tongue movement may be related to many factors, so it is recommended to consult doctor for clear diagnosis.