Most typically developing children make some mistakes as they learn to say new words. A speech sound disorder occurs when mistakes continue past a certain age. Every sound has a different age range when substitutions are considered developmentally appropriate. There are two types of speech sound disorders: articulation (making sounds) and phonological (sound patterns).
An articulation disorder involves problems making sounds. Sounds can be substituted, omitted, left off, added or distorted. These errors may make it hard for people to understand what your child is saying. Some errors are consider typical as children learn to speak. For instance, many young children sound like they are making a "w" sound for an "r" sound (e.g., "wabbit" for "rabbit") or a child may leave sounds or syllables out of words, such as "nana" for "banana." .
A phonological process disorder involves patterns of sound errors. For example, substituting all sounds made in the back of the mouth like "k" and "g" for those in the front of the mouth like "t" and "d" (e.g., saying "tup" for "cup" or "das" for "gas"). Another common phonological process is cluster reduction in which the child only produces one or the two consonants in a word (e.g., "boken" for broken or "poon" for spoon).
Stuttered speech often includes repetitions of words or parts of words, as well as prolongations of speech sounds. These disfluencies occur more often in persons who stutter than they do in the general population. Some people who stutter appear very tense or "out of breath" when talking. Speech may become completely stopped or blocked. Blocked is when the mouth is positioned to say a sound, sometimes for several seconds, with little or no sound forthcoming. After some effort, the person may complete the word. While everyone uses interjections such as "um" or "like” at times, excessive usage may distract the communication partner.
Everyone is dysfluent from time to time. It is fairly common in preschool children to stutter for a short period. It is the amount of dysfluencies, type and impact on overall communication, and age that determines if it is a disorder and requires therapeutic intervention.
While listening to your child speak, assessment of the resonance (nasal quality), pitch (tone), intonation (ability to change pitch), and quality (general function of vocal cords) will be evaluated. Use of the vocal folds and breathing to produce sound (e.g., the voice can be abused from overuse or misuse and can lead to hoarseness or loss of voice).
If there are concerns with your child’s vocal quality, other professionals may be recommended to determine if there is a structural, functional or abusive problem and whether therapy will help.
Dysarthria is a motor speech disorder. It results from impaired movement of the muscles used for speech production, including the lips, tongue, vocal folds, and/or diaphragm. The type and severity of dysarthria depend on which area of the nervous system is affected. Compensatory strategies can help a child articulate more clearly to help increase intelligibility.
Childhood Apraxia of Speech (CAS) is a neurological motor speech disorder. Children with CAS have problems saying sounds, syllables, and words. This is not because of muscle weakness or paralysis. The brain has problems planning to move the body parts (e.g., lips, jaw, tongue) needed for speech. The child knows what he or she wants to say, but his/her brain has difficulty coordinating the muscle movements necessary to say those words.