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Why Do I Slur My Speech When I Get Hammered?

Hint: Your brain is taking a bath in booze.

Other than stumbling around, yelling like a maniac, or trying to take your pants off over your head, slurred speech is probably the biggest stereotypical marker of being shitfaced.

“Bartenders, police officers, and hospital workers routinely identify drunks by their slurred speech,” Fenella Saunders writes at Discover Magazine in a piece about identifying drunkenness. “Several investigative groups judged the captain of the grounded Exxon Valdez oil tanker to be intoxicated based solely on the sound of his voice in his radio transmissions.”

Average people assume a slurred speaker is a drunk one too, and a few studies have looked at how booze changes perceptions of our speech. (Birds slur their songs when drunk, too.) One looked at whether listeners could identify which spoken, taped sentence among several sentences was uttered after a drink. In another, college students and Indiana state troopers had to guess whether a sentence spoken in isolation came from a drunk or sober mouth. They had no trouble identifying the drunk person.

In both studies, researchers found that listeners were able to “significantly discriminate” whether the speakers were sober or intoxicated by speech alone. It’s because the drinking produced increased “latency,” or a marked delay in speech. (You might also talk louder when drunk, because the booze has affected your hearing.)

“When you drink, every party of your brain gets bathed in alcohol, and the more you drink, the more these parts get bathed,” Aaron White, a senior scientific adviser at the National Institute on Alcohol Abuse and Alcoholism, told MEL.

White says this typically happens at about a blood alcohol content of .08, which is when everything has gone sort of slow-mo: the world, your reaction time, your coordination, your face, your friend’s face, your dog’s face, your thinking and your mouth.

“Alcohol doesn’t affect all brain areas the same, and some are a little more robust in the face of alcohol, but a few of the speech areas are fairly easy to disrupt.”

White says there are two areas specifically that are suckers for booze: the supplementary motor area, which is associated with speech production, and the Broca’s area, which controls language processing — where the signal goes that generates actual words. “The supplementary motor area is particularly sensitive to alcohol compared to other areas of the brain,” White said. “It’s significantly disrupted at .08, and for some reason it gets slowed down more profoundly and interfered with more by alcohol.”

When the supplementary motor area and Broca’s decide to get together and knock back a few drinks, it “leaves the individual with difficulty initiating speech, and controlling and keeping that initiating going,” White said.

The question, then, is why doesn’t everybody slur their words when they drink? We all know drinkers who slur after a few measly drinks, and others who could recite the Gettysburg Address with perfect enunciation after eight. White says that comes down to individual differences in brain chemistry, wiring, neuroanatomy, language skills and certainly tolerance.

“People who have much higher functioning language areas are more resilient to these effects. If the brain is highly tuned to produce speech articulately due to genetics or training, if those areas are exercised a lot, they are probably more resilient.”

This is why slurred speech isn’t necessarily a good indicator of drunkenness. Just because we may be able to tell by someone’s speaking that they’ve been drinking some, we can’t necessarily tell how drunk they actually are. Back at Discover, Saunders mentions a study led by phonetician Harry Hollien at the University of Florida. Hollien had subjects listen to recordings of people who were sober, mildly buzzed, legally drunk, and totally hammered, and rate how drunk they presumed the speaker to be. He also got actors to fake being various levels of drunk for the tape, too.

The result: The listeners consistently mistook the mildly inebriated people as more drunk than they were. They consistently thought the super-smashed people were not that drunk. And the actors were able to fool everyone. “Mild drinkers might come under needless suspicion, and seeming drunks can sometimes put up a surprisingly sober, dangerous fight,” Saunders concludes.

While White says that presumably drunken speech goes along with other diminished cognitive functions, it shouldn’t be assumed that one impairment leads to another. “It’s very hard to know based on one impairment, unless you’re extraordinarily drunk, how impaired other functions are,” White said. “Just as there are people who black out at moderate BACs, there are people who are blackout and you could never tell. You listen to them speak, watch them walk, and never know. One impairment doesn’t necessarily tell you about the others. Alcohol does not have a uniform effect across the entire brain, unless the brain stem is about to get turned off, and then you’re going to die.”

But if you’re just drunk enough to slur your speech, the more likely risk is just embarrassing yourself. White says it’s not really possible to prevent slurring once you’ve hit the slurring sweet spot, so all you can do is recognize when it’s happening and try to dial it back.

“All you can do is sober up,” he said. “Just put your phone away, don’t text anyone, and wait to sober up before you communicate.”