learning difficulties

This book addresses learning difficulties, which have been and continue to be the focus of discussion among educators at various educational levels. What is meant by this phenomenon?
There are many definitions of learning difficulties, the most common of which is that a person exhibits a problem in one or more of the following areas: the ability to use or understand language, or the ability to listen, think, speak, read, write, or perform simple arithmetic operations. These symptoms may appear together or individually. Alternatively, a child may have a problem in two or three of the above.
Learning difficulties mean a problem with academic achievement in reading, writing, or arithmetic. This is often preceded by indicators such as difficulties learning spoken language. The child exhibits a delay in language acquisition, often accompanied by pronunciation problems.