Language delay

Language delay is a failure in children to develop language abilities on the usual age appropriate for their developmental timetable. Language delay is distinct from speech delay, in which the development of the mechanical and motor aspects of speech production is delayed.

Oral communication is a two-stage process. The first stage is to encode the message into a set of words and sentence structures that convey the required meaning, i.e. into language. In the second stage, language is translated into motor commands that control the articulators (organs and structures such as the lungs, vocal cords, mouth, tongue, teeth, etc.), thereby creating speech, i.e. orally-expressed language.

Because language and speech are independent, they may be individually delayed. For example, a child may be delayed in speech (i.e., unable to produce intelligible speech sounds), but not delayed in language. However a child with a language delay typically has not yet been able to use language to formulate material to speak; he or she is therefore likely to have a delay in speech as well.

Language delay is commonly divided into receptive and expressive categories. Receptive language refers to the process of understanding what is said to the subject. Expressive language refers to the use of words and sentences to communicate messages to others. Both categories are essential to effective communication.

Language delay is a risk factor for other types of developmental delay, including social, emotional, and cognitive delay. Some children may grow out of these deficits, even coming to excel where they once lagged, while others do not. One particularly common result of language delay is delayed or inadequate acquisition of reading skills. Reading depends upon an ability to code and decode script (i.e., match speech sounds with symbols, and vice versa). If a child is still struggling to master language and speech, it is very difficult to learn another level of complexity (writing). Thus, it is crucial that children have facility with language to be successful readers.

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