This work aims to bring together a wide–ranging set of clinical linguistic case studies covering all levels of linguistic analysis and demonstrating the application of more than one level of linguistic analysis to individual cases. It focuses on patient–driven cases. The authors aim to demonstrate the collaborative nature of applied linguistics by illustrating the kind of service that speech and language therapists may reasonably ask of linguists, without feeling that they need have expertize in this area themselves. The case studies include a representative range of communication disorders and involve a wide range of areas of linguistics and phonetics. Most of the studies incoporate complementary analysis at several linguistic levels, and involve a wide variety of analytical techniques including standard assessments and profiling procedures, instrumental and computational procedures, and improvised materials tailored to the specific nature of individual cases.