WHAT IS "SPEECH?"
Speech is the process by which sounds, syllables, and words are formed when the jaw, teeth, tongue, lips, and palate alter the airstream coming through the vocal folds. It is also known as articulation. Intelligibility is a measure of how well speech can be understood. Someone with an 'articulation disorder' can be hard to understand because they say sounds incorrectly. Most errors fall into one of three categories: omissions, substitutions, or distortions. An omission might be 'at' for 'hat' while a substitution may be 'wabbit' for 'rabbit' or 'sum for 'thumb.' When the sound is pronounced inaccurately, but sounds something like the intended sound, it is called a distortion.
Speech acquisition is a gradual process that requires years of practice. During this process, a child learns how to regulate the muscles in his mouth, e.g., lips, jaw, tongue, to produce understandable speech. However, by the first grade, roughly 5 percent of children continue to have noticeable speech or articulation difficulties, the majority of which have no known cause. Most articulation difficulties in the preschool years occur in children who are developing normally in all other areas. However, speech disorders may also occur in children who have developmental disabilities.
Source: Canadian Association of Speech-Language Pathologists and Audiologists