It is said that the typhoid fever patient has got coated tongue. It was usual practice of old and gold physicians to observe the tongue of each and every patient. I could never get any such information and do not fallow the practice of observing the tongue of the patient. Some experienced physician needs to edit this answer.

NO! unless your tongue is coated with sperm...

This is the symptoms of tongue sore ,Get the treatment in the beginning stage itself.

When your tongue is coated in a white fungal substance, that is known as thrush. Thrush can be caused by antibiotic usage and is treated with anti fungals.

No, most frog's tongues , are coated with a sticky saliva in order to catch prey.