hi, thank you for your query- the loss of sensation near the side of mouth is commonly due to paralysis of facial nerve called bell s palsy. the loss of voice can be due to the same. or some of the other causes include- 1.Laryngitis-Laryngitis is an inflammation of the larynx, or voice box, causing hoarseness and loss of voice. 2.Sjogren s syndrome- an autoimmune disorder that most often causes dry eyes and dry mouth. 3.Strained voice (vocal cords)-symptoms of a strained voice include hoarseness, raspy voice, rawness, achy throat, deeper voice. 4.Tonsillitis-Tonsillitis is painful swelling in the tonsils, causing sore throat, red tonsils, pain, fever 5.Viral pharyngitis-Viral pharyngitis is a sore throat caused by a virus, and causes throat pain and cold-like symptoms. 6.Dehydration (Adult)-Dehydration, or not getting enough fluid, causes low blood pressure, weakness, dizziness, fatigue, and nausea. 7.Dry mouth syndrome (xerostomia)-People with dry mouth syndrome have a chronic feeling of dryness in their mouths. thank you, wishing you good health