By the age of 4, phonological processes are usually gone from children’s speech and their speech patterns are easily understood. Some individuals, however, fail to use speech sounds that are appropriate for their age, thus resulting in a phonological disorder. Developmental phonological disorders are characterized by individuals’ failure to produce the sounds expected of their developmental level. “Developmental Phonological Disorders”, also known as Phonological Impairment (PI) or Phonological Disorders, are a group of language disorders that affect children’s ability to develop easily understood speech by the time they are four years old, and, in some cases, their ability to learn to read and spell. Therefore, Phonological disorders involve a difficulty in learning and organizing all the sounds needed for clear speech, reading and spelling.
A common misconception about developmental phonological disorders is that they are articulation disorders, affecting only the motor aspects of speech production. Phonological disorders, in reality, are truly language disorders. The problem lies in their ability to organize these sounds into a system of sound patterns therefore causing impairment in the use of spoken and/or written language. These communication disorders not only inhibit speech, but research has shown that they may also affect children’s ability to learn to read and spell. In order to pronounce most sounds and sound sequences of English, a child must be able to recognize and store new lexical items, plan and execute articulatory movements necessary for production of these new items, compare the adult input with his or her own output, then modify his or her production if the two do not match.A phonological impairment, then, can be reflected in difficulty articulating sounds or a deficit in how sound information is stored and retrieved in the mental lexicon .