Relationships between speech delivery and speech effectiveness

Six speech delivery variables—volume, rate, voice quality, posture, gesture, and bodily movement—were varied within a five‐minute persuasive speech. The speech was delivered in each of ten conditions by the same speaker in the same environment. The resultant video‐tapes were validated and shown to more than 220 subjects. The findings of this phase of the research indicated that speech delivery, as operationally defined in this study, had virtually no effect on attitude change, recall‐comprehension, or ethos. Further investigation using vitiated evidence in the speech indicated that in "composition ineffective" conditions, delivery contributed significantly to some measures of speech effectiveness. However, the greatest variance in most measures emerged in connection with the composition of the speech, with speech delivery being an augmenting variable in "ineffective composition" conditions.