Typical Speech Development – Identifying Speech Disorders
Our goal is to illustrate stages of typical vocal development which clinicians need to understand to determine level of severity of speech delay or disorder based on observation of children’s speech patterns. These clips show typical early speech development in children beginning at the earliest stages in infancy and continuing through age 4 when speech is largely understandable to many listeners. These clips of typical development can be used for comparison with clinical observations of speech-disordered clients at various ages and severity levels to explore why the clients are considered speech disordered related to expectations for typical development.
Clinicians need to make qualitative judgments about the severity level of client's speech delay or disorder. The terms frequently employed by clinicians include mild, moderate, and severe. Many factors are considered whem making valid judgments about severity level. These include
- Overall intelligibility
- Causal factors
- Potential impact on the child’s communication in daily living
- Family and cultural expectations for speech development.
One specific factor frequently used in determining severity is a difference between the child's chronological age and their speech “developmental age”. “Developmental age” expectations are based on the clinician's understanding of the child’s speech in relationship to typical speech development milestones. A five year old may be producing speech that sounds like a normally developing two year old.
Mismatches between developmental expectations and chronological age indicate speech delay. Error patterns that are not seen during typical development are indicative of speech disorder. Some examples include substitution of a glottal stop for all other consonants or pervasive nasality on all sounds.
Judgments of severity are important for several reasons.
- Predictions of prognosis and length of therapeutic intervention are often based on judgments of severity, as well as other factors.
- Information about severity is important when communicating with families.
- Quantification of severity may be a part of qualifying clients for services in both educational and medical settings.
These judgments also impact decisions about the frequency and intensity of intervention. Statements of severity do not link to decisions about the type of intervention most beneficial for a child. Severity also does not help clinicians determine the cause for a child’s speech delay or disorder.
For more information, contact Barbara Davis or Lisa Bedore.