Effects of Synthesized Voice Warning Parameters on Perceived Urgency

The effects of synthesized voice warning parameters on perceived urgency were examined in order to build a detailed and usable description of the relation between the parameters of synthesized voice warnings and perceived urgency. Ten native and 10 non-native English speakers participated in 4 experiments to evaluate and quantify the effects of the voice parameters. The results showed that speech rate, average fundamental frequency (F0), voice type, and fundamental frequency contour have clear effects on the perceived urgency of synthesized voice warnings. The effects of quantitative parameters on perceived urgency were scaled using an application of Stevens's power law (1957). In addition, the results showed significant differences in the perceived urgency of average F0 and F0 contour types between native and non-native English speakers. Implications of the results for the design and improvement of synthesized voice warnings are discussed.