Six types of speech synthesis were evaluated for comprehensibility: Standard Linear Predictive Coding Analysis/Resynthesis; Pitch Synchronous Analysis/Resynthesis; Pitch Synchronous Multi-Pulse Analysis/Resynthesis; and three PSOLA (Pitch Synchronous Overlap-and-Add) techniques. The relative comprehensibility of the synthesis types was tested by using the synthesised speech to convey information that subjects needed in order to perform a diagram-based multiple-choice task. Keywords: Speech Synthesis; Evaluation; Multi-Pulse Linear Predictive Coding; PSOLA