Products that contain bismuth can temporarily turn your tongue black, according to Atlas of Adult Physical Diagnosis. Other Causes If you have a black tongue, then you could have a fungus called Aspergillus niger growing on the surface of your tongue. If you have too much bacteria growing in your mouth, it could cause your tongue to appear black and hairy, according to the Mayo Clinic.
In addition, a child is said to have a cognitive delay and/or a learning disability when they are performing at least two grade levels below their peers. For example, a third grade class is learning their multiplication tables, but a student with a cognitive delay would be performing math on a first grade level.
Late bloomer can refer to children who suffer from delayed puberty, who are late in reaching their full height. W. B. Yeats (age 30), Pierre Trudeau (age at least 28), Mark Twain (age 34), and Johann von Goethe (age 39) are all late bloomers in this last sense. In most public educational systems, children and adolescents of the same age are put in the same classes.