|Speech disorders or speech impediments, as they are also called, are a type of communication disorders where 'normal' speech is disrupted. This can mean stuttering, lisps, etc. Someone who is totally unable to speak due to a speech disorder is considered mute.
Classifying speech into normal and disordered is more problematic than it first seems. By a strict classification, only 5% to 10% of the population has a completely normal manner of speaking (with respect to all parameters) and healthy voice; all others suffer from one disorder or another. Stuttering is quite common. Cluttering, a speech disorder that has similarities to stuttering. Dysprosody is the rarest neurological speech disorder. It is characterized by alterations in intensity, in the timing of utterance segments, and in rhythm, cadency, and intonation of words. The changes to the duration, the fundamental frequency, and the intensity of tonic and atonic syllables of the sentences spoken, deprive an individual's particular speech of its characteristics. The cause of dysprosody is usually associated with neurological pathologies such as brain vascular accidents, cranioencephalic traumatisms, and brain tumors.
Speech sound disorders involve difficulty in producing specific speech sounds (most often certain consonant, such as /s/ or /r/), and are subdivided into articulation disorders (also called phonetic disorders) and phonemic disorders. Phonetic disorders are characterized by difficulty learning to physically produce sounds, and are popularly referred to as "speech impediments". (However, this term is archaic. The acceptable, modern term is "speech impairment.") Phonemic disorders are characterized by difficulty in learning the sound distinctions of a language, so that one sound may be used in place of many. However, it is not uncommon for a single person to have a mixed speech sound disorder with both phonemic and phonetic components.
Voice disorders are impairments, often physical, that involve the fuction of the larynx or vocal resonance.
Dysarthria is a weakness or paralysis of speech muscles, often caused by damage to the nerves, muscles, and/or brain. Dysarthria is often cause by strokes, parkinsons disease, ALS, head or neck injuries, surgical accident, or cerebral palsy.
Apraxia of speech may result from stroke or be developmental, and involves inconsistent production speech sounds and rearranging of sounds in a word ("potato" may become "topato" and next "totapo"). Production of words becomse more difficult with effort, but common phrases may sometimes be spoken spontaneously without effort. It is now considered unlikely the childhood apraxia of speech and aquired apraxia of speech are the same thing, though they share many characteristics.
In many cases the cause is unknown. However, there are various known causes of speech impediments, such as "hearing loss, neurological disorders, brain injury, mental retardation, drug abuse, physical impairments such as Cleft lip and palate, and vocal abuse or misuse." Child abuse may also be a cause in some cases.
Many of these types of disorders can be treated by speech therapy, but others require medical attention by a doctor in phoniatrics. Other treatments include correction of organic conditions and psychotherapy.
In the United States, school-age children with a speech disorder are often placed in special education programs. More than 700,000 of the students served in the public schools’ special education programs in the 2000-2001 school year were categorized as having a speech or language impairment. This estimate does not include children who have speech/language problems secondary to other conditions such as deafness". Many school districts provide the students with speech therapy during school hours, although extended day and summer services may be appropriate under certain circumstances.
Patients will be treated in teams, depending on the type of disorder they have. A team can include; SLP's, specialists, family doctors, teachers,and parents/family members.