Everyone has circumvallate papillae at the base of their tongue. in most cases, they are not as prominent as these. They are simply a form of specialized taste bud. The white material in front of them are normal filiform papillae which are highlighted due to flashback when the photo was taken.
They are located along the “circumvallate line” and contain taste buds that confer the sense of sour and bitter to the back of the tongue. They can actually be quite prominent and are often mistaken by patients for cancerous growths.