Dog's tongue is crooked and cannot be extended back. This is dog tongue paralysis, which is similar to facial paralysis. It may be caused by stroke, high blood pressure, epilepsy, increased intracranial pressure, etc. You need to go to the hospital for examination to determine the specific cause and timely treatment. This situation is also more likely to occur if the dog is over ten years old. Another condition is rabies, but rabies is also accompanied by other symptoms such as photophobia, inability to bark, mania, convulsions, etc., so it is easy to distinguish.