Hello, Possible reasons for a coating on the tongue include: -yeast infection, thrush -gastric upset -acid reflux -mouth with soft tissue infection -dental abscess draining from a tooth -periodontal disease -mouth breathing -dry mouth -other medications or health issues Bad breath can be associated with these conditions. An increase in the size of your tongue due to inflammation can affect your speech. A growth or tumor is possible. Other disease states can have side effects that could affect the function of your tongue. I am glad that you clean your tongue daily. Be sure to practice good daily dental care. Warm salt water rinses have a cleansing and soothing effect. Be sure to keep well hydrated, proper nutrition, and balanced vitamins. You describe a change in the size of your tongue which could indicate swelling. You should rule out an allergic reaction. Think of any changes you may have made such as using a new dental product or change in your diet. Eliminate any possibilities and evaluate the result. You can try some anti-inflammatory medications such as acetaminophen and advil. An antihistamine such as benedryl may help, but can make you tired. These may reduce your symptoms and offer some relief. There are oral rinses that may be helpful such as chlorohexidine gluconate which reduces bacteria in the mouth or betamethasone sodium phosphate which is a corticosteroid used to reduce mouth soreness. You should schedule a dental exam. A routine exam and cleaning will evaluate your dental health. Periodontal disease and dental infections must be ruled out. Your dentist will review your overall health. Antibiotics or precription medication may be needed. A diagnosis will be needed to decide the best treatment. You want to evaluate for a more serious condition and possible need for a physical or blood tests. I hope this information offers you some relief and thank you for your inquiry.