There is little published intervention outcome literature concerning dysarthria acquired from stroke. Single case studies have potential for more detailed specification and interpretation than is generally possible in larger studies so are informative for clinicians dealing with similar cases. Such research also contributes to planning of larger scale investigations. Behavioural intervention is described which was carried out between 7 - 9 months after stroke with a 69-year-old man with severe dysarthria. Pre-intervention stability between 5 -7 months contrasted with post-intervention gains. Significant improvement was demonstrated using randomized, blinded assessment by 10 judges on measures of word and reading intelligibility and communication effectiveness in conversation. A range of speech analyses were undertaken (rate, pause, and intonation characteristics in connected speech and single word phonetic transcription), with the aim of identifying speech components which might explain the listeners ' perceptions of improvement. Changes were detected mainly in parameters related to utterance segmentation and intonation. The basis of post-intervention improvement in dysarthria is complex, both in terms of the active therapeutic dimensions and also the specific speech alterations which account for changes to intelligibility and effectiveness.