In Japan, vehicle horns are used as a means of communication between drivers, and frequently induce negative psychological reactions. Horn sounds with the acoustic features of speech could facilitate communication between drivers and improve hearers' negative impressions. To investigate these hypotheses, psychoacoustical experiments were conducted using synthesized horn sounds with the acoustic characteristics of the Japanese words including “abunai”, which means “dangerous.” Spectral features and temporal envelopes were extracted from spoken words and from non-words with an altered syllable order, and were applied to horn sounds. Two experiments were carried out to examine the effects of acoustic characteristics of horn sounds on the perceived quality of them and interpretations of the intention behind another driver's horn use. Stimuli with spectral characteristics of a spoken word “abunai” and those of a non-word with an altered syllable order were rated as being less unpleasant and safer than the original horn sound. However, the stimulus with spectral characteristics of a spoken word was interpreted to signal “caution” and “danger”. These results suggest that a horn sound with the spectral characteristics of a spoken word has a better perceived quality than an actual horn sound, and can communicate the intention behind another driver's horn use.