What exactly does it mean when your tongue is always coated white?

Hygiene: Could mean you're just not cleaning your tongue well and overall oral hygiene needs to be better. It may also be fungal in nature and not have anything to do with hygiene. Contact your dentist to possible prescribe a solution to your problem.

Tongue coatings: Patients perceive things differently from dentists who examine mouths, teeth, tongues, etc. Every day. It may be completely normal papillae, a plaque of food debris, bacteria and dead cells, or something more serious as a fungal infection, lichen planus, leukoplakia, etc. It's best to have your own dentist examine you and tell you exactly what it is and if anything needs to be done for it.