Speech language pathologists (SLPs) and educational professionals use a variety of tools to diagnose developmental language disorder (DLD) in children. Some of these tools are well-validated for diagnosing DLD and some are not. You may find yourself in a position to advocate for better practices to be adopted in your state or school district. Below are links to tools that are commonly used or might be used as part of best practice. This information may evolve over time, particularly links to specific tests, and is current as of Dec. 2018.
Assessing Developmental Language Disorder
- Screen for language to identify children with DLD. Prior to the onset of reading difficulties, children are most often referred for speech sound errors. Speech disorders often co-occur with DLD, but treatment of speech will not resolve difficulties with grammar and vocabulary. Language disorders are often under-identified, especially when they do not co-occur with other difficulties.
- Assess receptive and expressive morphology and syntax and expressive vocabulary; receptive vocabulary alone is not likely to be a sensitive marker of DLD. The most sensitive markers in Mainstream American English appear to be verb markers (am, is, are, plays, jumped). These markers tend to be most useful with younger children (under age 9). At older ages, assessment should focus on the understanding and use of complex grammar, discourse, and figurative language. Reading problems as well as grammar and spelling errors in written language may be characteristic.
- Assess verbal working memory. Sentence repetition tasks tap phonological sequencing or morphosyntax and working memory and tend to be fairly sensitive markers. Assessments that tap working memory may be more useful than composite scores that incorporate unaffected areas of language (e.g., single word receptive vocabulary).
- Consider the role of functional impact. Though strong standardized measures do not exist to assess functional impact of language difficulties relative to peers, some measures do exist that allow assessment of everyday functioning. As currently designed, these tools may not be useful for diagnosis, but may be useful for documenting change following treatment. One example would be the FOCUS. Consideration of parent and teacher reports about how communication difficulties affect participation in everyday life should be considered. Limited academic success, even with the addition of Response to Intervention (RTI) or Multi-tiered Systems of Support(MTSS) in place may be another way to document functional impact.
- Consider the role of dialect on valid assessment. African American English and Southern White English change how verb markers are used, which invalidates tests that rely heavily on verb morphology. It is not sufficient to use alternative scoring procedures if those procedures were not adequately normed. This leads to both over and under identification. These tests were developed to be dialect-neutral and were normed on US populations:
- Consider children learning English as an Additional Language. Expect deficits in both languages; deficits in only one language suggest limited exposure to that language, rather than DLD. Dynamic assessment can differentiate DLD from limited exposure. Best practice is to assess in both languages, with assessment carried out by a fluent (native) speaker. Un-normed alternative scoring procedures & translated tests are not adequate and can be misleading. These tests were explicitly developed for bilingual (Spanish/English) children in the US. New tests are being developed and should be explored as they become available (SPELT, CELF).
- Sometimes assessment in both languages is not possible. In this case, consider using tools that correct for limited English exposure. This tool was developed in Canada but is likely appropriate for use in the US.
- Consider co-occurring disorders. In these cases, DLD co-occurring with X or Language Disorder associated with X is the preferred term. For instance, DLD can co-occur with Dyslexia. A child may be diagnosed with both disorders. Discrepancy criteria are not valid. Nonverbal IQ above 80 is not required to diagnose DLD. Language Disorder associated with Intellectual Disability may be used when IQ is below 70 +/- SEM.