Children with language disorders have difficulty understanding and/or producing language, spoken or written, at the expected age levels. A receptive language disorder refers to a difficulty understanding language and trouble comprehending what they hear or read. Expressive language disorder refers to difficulty talking or expressing ideas.
A language disorder is impaired comprehension and/or use of spoken, written and/or other symbol systems. The disorder may involve (1) the form of language (phonology, morphology, syntax), (2) the content of language (semantics), and/or (3) the function of language in communication (pragmatics) in any combination.
1. Form of Language
Phonology is the sound system of a language and the rules that govern the sound combinations.
Morphology is the system that governs the structure of words and the construction of word forms.
Syntax is the system governing the order and combination of words to form sentences, and the relationships among the elements within a sentence.
2. Content of Language
Semantics is the system that governs the meanings of words and sentences.
3. Function of Language
Pragmatics is the system that combines the above language components in functional and socially appropriate communication. (asha.org)