This term is used when there is an acquired language disability in any language modality - speaking, listening, reading and writing. There are a wide variety of aphasia symptoms, depending on which language modality is affected.
Expressive language disorder
A person has difficulty communicating using language, but his / her ability to understand language is normal / less affected. For example, a child will be able to follow a simple instruction but have a limited vocabulary.
Receptive language disorder
A person will have difficulty understanding spoken, and sometimes written, language. Often has difficulty organizing their thoughts and communicating.