Small buds language can sometimes have a black color due to the accumulation of bacteria and fungi.
Also, the surface language can be changed for food, drinks, cigarettes, poor oral hygiene. This state language is for sure, but it looks very uncomfortable.
As black tongue, yellow tongue is the result of accumulated bacteria. The solution is proper oral hygiene and constant water consumption.
It is a disease of the mucous membrane of the oral cavity with the fungi of the genus Candida, which often affect people with low immunity. The same can occur in patients who drink strong antibiotics.