Effects of ethanol intoxication on speech suprasegmentals

The effects of ingesting ethanol have been shown to be somewhat variable in humans. To date, there appear to be but few universals. Yet, the question often arises: is it possible to determine if a person is intoxicated by observing them in some manner? A closely related question is: can speech be used for this purpose and, if so, can the degree of intoxication be determined? One of the many issues associated with these questions involves the relationships between a person's paralinguistic characteristics and the presence and level of inebriation. To this end, young, healthy speakers of both sexes were carefully selected and sorted into roughly equal groups of light, moderate, and heavy drinkers. They were asked to produce four types of utterances during a learning phase, when sober and at four strictly controlled levels of intoxication (three ascending and one descending). The primary motor speech measures employed were speaking fundamental frequency, speech intensity, speaking rate and nonfluencies. Several statistically significant changes were found for increasing intoxication; the primary ones included rises in F0, in task duration and for nonfluencies. Minor gender differences were found but they lacked statistical significance. So did the small differences among the drinking category subgroups and the subject groupings related to levels of perceived intoxication. Finally, although it may be concluded that certain changes in speech suprasegmentals will occur as a function of increasing intoxication, these patterns cannot be viewed as universal since a few subjects (about 20%) exhibited no (or negative) changes. (C) 2001 Acoustical Society of America.