The experts selected several well-known tongue twisters and measured how exactly the way of pronunciation changes depending on the amount of alcohol per million in the blood. The volunteers were repeatedly recorded while sober and then after drinking large amounts of alcohol and during six hours of sobering up. Based on the results of the voice analysis, they were able to determine with 98 percent accuracy the expressions that arose under the influence of alcohol. Their test was conclusive from a level of 0.8 per thousand of alcohol in the blood, which is the limit of tolerance for drivers in the USA.

The study, published in the Journal of Studies on Alcohol and Drugs, was conducted with a limited sample of 18 respondents. The researchers cautioned that future usability will depend on collecting more data from different speakers. Ethnic origin or the situation in which the voice is recorded can affect the analysis.

One of the co-authors of the research, Brian Suffoletto of Stanford University, is optimistic about the possible future use. “It is offered, for example, with the electronic ignition lock in cars, which would not let the engine start if the person in question did not pass the voice test. This can be useful, for example, for professional drivers such as school bus drivers or heavy machinery operators who are at risk of public safety,” he said. “Another application can be in bars and restaurants, where it can be a guide for the service when to stop pouring for the guest,” he added.