Why my tongue is white for about two months?

May be fungal infection thrush especially if diabetic or immunocompromised by other condition May be hypertrophic papillae from dry mouth alcohol dehydration smoking or may be other etiologies like orla licehn planus-an inflammation , leukoplakia-chronic irritation from smoking or other causes . F/u/ w/ MD-ear nose throat https://www.mayoclinic.org/symptoms/white-tongue/basics/causes/sym-2005067

A “white tongue” is a common symptom when your tongue is coated by a thick white film. This coating can cover the entire surface of your tongue, the back part of your tongue or it might show up in patches. You might also notice a bad taste in your mouth, bad breath or redness. Try brushing your tongue lightly with a toothbrush to remove it. If not please see a provider for diagnosis.