Professionals across disciplines who assess and teach students with language problems should develop their own standards for best professional practices to improve the diagnostic and treatment (instructional) services in schools and nonschool settings rather than assessing only for eligibility for categories of special education services according to federal and state special education laws. Participation of professionals from multiple disciplines on teams is necessary but not sufficient unless cross-disciplinary conceptual frameworks are developed and used. Best practices for assessment and intervention for language problems should take into account the patterning of test and other assessment data within 3 kinds of profiles: (1) domains of development--cognition/memory, oral language, sensory and motor, attention and executive function, and social emotional; (2) academic skills--reading, writing, and math; and (3) phenotypes specific to neurogenetic or neurodevelopmental conditions that may apply to the case at hand. (Contains 2 figures and 1 table.)