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.
Maturation delay, also called developmental language delay, is one of the most common types of language delay. Children with a maturation delay may be referred to as late talkers or late bloomers.. Maturation delays frequently run in families.anguage delay may result from a variety of underlying disorders, including the following: 1  mental retardation. 2  maturation delay (This delay in the maturation of the central neurological processes required to produce speech is often the cause of late talking.).