Delayed Phonological Development

Phonological development is an aspect of language development that involves specifically the ability to use speech sounds to transmit meaning. Each language has a unique system for organizing speech sounds into categories, with each contrastive category called a phoneme (e.g., p versus b contrasts two phonemes in English that allows one to distinguish pat and bat as words with different meanings in oral spoken language). Children with delayed phonological development have difficulty learning the system of sound categories and contrasts and misarticulate (mispronounce) the speech sounds used in the languages they are learning.

This entry focuses on primary delays in phonological development, although such delays can be secondary to conditions that impair access to speech input (e.g., hearing impairment), the ability to understand the speech sound system of the input language (e.g., Down syndrome and other causes of intellectual impairment), or the structure and function of the articulators (e.g., craniofacial disorders such as cleft palate). The etiology of primary delayed phonological development is discussed, first, in relation to biological and social risk factors (distal causes) and, second, with respect to cognitive–linguistic processes that underlie the speech errors produced by children with this developmental problem (proximal causes). Subsequently, the characteristics of different subgroups of children with delayed phonological development are described alongside recommended treatment options.

At school entry, approximately 12% of children present with delayed phonological development; that is, listeners find the child’s speech to be unclear and difficult to understand or unusually inaccurate. Diagnosis can be made at any age, however, regarding various milestones along the path toward the achievement of adultlike speech accuracy. Specifically, toddlers are not expected to produce speech sounds accurately, but they should produce many different speech sounds representing the major classes of sounds in the input language (in English, glides such as w, liquids such l, stops such as b, and fricatives such as f).

By the age of 4 years, the child should produce speech that can be understood by a stranger. By the time a child enters school, he or she should be producing all speech sounds accurately more often than not, even though some difficult words may be mispronounced and some late-developing sounds may be slightly distorted. Finally, by the age of 8 or 9 years, all children should be producing speech with adultlike levels of accuracy, although refinements in precision continue through late adolescence.