Speech includes the fine motor control of the muscles of the jaw, lips, tongue and their coordination with respiration. There may be several reasons for speech impairments. Children develop the speech sounds of their language they are exposed gradually, as they develop more muscle control and movement patterns. Sometimes they have substitutions or distortions beyond what would be considered to be the age of mastery for some sounds. They may be due to underdeveloped listening skills, impaired hearing acuity. Imprecise speech may also be due to neurological impairments such as Parkinson’s Disease, Traumatic Brain Injury (TBI), Stroke (CVA) or Cerebral Palsy (CP). In addition, structural issues such as due to tongue tie or micrognathia, or motor planning issues such as apraxia, may impact a person’s speech precision. The best outcome includes a full oral peripheral exam to determine the range of motion, agility, speed, coordination and strength of all of the components as well as to examine all of the possible structures and restrictions.
A feeding evaluation is always performed to further look at muscle function as the articulators share all of the same muscles for the oral phase of swallowing. A formal or informal articulation test provides an inventory of speech productions that are age appropriate when compared to same aged peers. There are various speech sounds that are expected at different ages which need to be considered. All of the speech sounds are expected to be mastered by 8 years of age. However, although individual speech sounds may sound precise, the placement may be incorrect and observed this provides information regarding why that is so.
Certain sound production errors are expected when considering a myofunctional disorder which may include any number of the following “s, z, sh, ch, zh, j, r, t, d, l, n” which are due to compensatory strategies used due to structural problems or habitual resting postures of the tongue and lips. Some speech disorders are due to poor sound discrimination as in phonological disorders which may be more of a sound processing problem related to Auditory Processing Deficit (APD).