This is a protocol for a Cochrane Review (intervention). The objectives are as follows:

To evaluate the effectiveness of speech and language therapy (SLT) interventions on speech and voice problems in people with Parkinson’s disease.

We will investigate whether:

SLT is more effective than no SLT;

SLT is more effective than placebo or attention control interventions;

one SLT intervention is more effective than another SLT intervention (including standard care).