Hi abracadabra,
It has been my experience that expressive language disorders may not be picked up in normative testing - both psycho educational as well as speech and language, unless the evaluator is savvy and willing to comment on the child's approach to various tests and qualitative assessments. I would agree that certain students can compensate or mask - or that many of the tests are just not able to measure some of the nuances of expressive language.
You ask whether or not there might be a discrepancy between the VCI and PRI on the WISC. My son's VCI scores always test higher than PRI - on one administration more than 25 points, yet he has expressive language weaknesses. So, I would say that while a much higher PRI might raise certain red flags, the WISC alone cannot test for the absence or presence of ELD. Within the overall test battery, the evaluator might use tests that could spot word retrieval issues, organizational issue, written expression and other skills that often are a part of ELD. But, generally a SLP (speech and language pathologist) would conduct more sensitive measures of language processing and expressive language.
What kinds of troubles do you see? Has your child been evaluated recently? Are there known LD's that might also be present?
The book, Childhood Speech, Language and Listening Problems by Patricia McAleer Hamaguchi is a good resource for understanding speech and language issues.
