A child with Learning Disabilities has problems with reading, spelling, and writing. These are language problems. Early speech and language problems can lead to later reading and writing problems. A child with LD may also have problems with math or social skills. LD has nothing to do with how smart your child is. Most people with LD have normal to above-average intelligence.
You may hear people say they have dyslexia. People with dyslexia have problems reading. Many children with reading problems have other language problems. This makes LD a better term to use. Other terms you may hear are language-based learning disabilities or specific learning disorder.