The existence of an aphasia-like language disorder in psychotic speech has been the subject of much debate. This paper argues that a discrete language disorder could be an important cause of the disturbance seen in psychotic speech. A review is presented of classical clinical descriptions and experimental studies that have explored the similarities between psychotic language impairment and aphasic speech. The paper proposes neurolinguistic tasks which may be used in future studies to elicit subtle language impairments in psychotic speech. The usefulness of a neurolinguistic model for further research in the aetiology and treatment of psychosis is discussed.