The essential feature is an impairment in expressive language development as demonstrated by scores on standardized individually administered measures of expressive language development which are substantially below the scores obtained from standardized measures of both nonverbal intellectual capacity and receptive language development.

Difficulties expressing oneself in speech.

some children have problems expressing themselves in speech. This is referred to as a developmental expressive language disorder. A child who often calls objects by the wrong names, has an expressive language disorder. An expressive language disorder can take other forms. A 4-year-old who speaks only in two-word phrases and a 6-year-old who can't answer simple questions also have an expressive language disability.