A review is undertaken of recent experimental studies of the effects of speech therapy offered to patients with Parkinson's disease. In contrast to earlier opinions based upon clinical impressions, the results of these studies indicate that the immediate gains from therapy measured within the clinical setting are readily detected, that these are perceived by patient's relatives and that there is reasonable evidence that benefits persist for some period after treatment. A further study is reported which tests the effects of a less intensive treatment regimen. This also gave positive results. Although questions remain regarding the most efficient form of treatment and the extent of its benefits outside the clinic, the existing results warrant greater optimism about the benefits of speech therapy offered to patients with Parkinson's disease.