Specific language impairment (SLI) and APD appear intertwined, with the suggestion that differential diagnosis may be influenced by whether a child is assessed by an audiologist or speech-language therapist. Multi-disciplinary assessment (as occurs at SoundSkills) is advisable.
Ferguson, M. A., Hall, R. L., Riley, A., & Moore, D. R. (2011). Communication, listening, cognitive and speech perception skills in children with auditory processing disorder (APD) or specific language impairment (SLI). Journal of Speech, Language, and Hearing Research.
Miller, C. A., & Wagstaff, D. A. (2011). Behavioral profiles associated with auditory processing disorder and specific language impairment. Journal of communication disorders, 44(6), 745-763.