It’s Sunday morning, and your voice is basically gone. After all, you were screaming for hours before bedtime just so your friends could hear you over the loud music blasting at the bar or concert where you spent your whole evening. We’ve all been there. It makes sense that you’d get louder when you’re competing with something loud like live music, but your voice also gets louder when that music is only coming through your headphones. It turns out that’s because your voice automatically adapts to loud noise all the time — unconsciously — because it’s wired that way. And humans aren’t the only ones that do it.
Étienne Lombard, a French otolaryngologist (an ear, nose, and throat doctor), discovered the “symptom of the raised voice” in 1909 and published an article detailing its effects in the journal Annales des Maladies de L’Oreille et du Larynx in 1911. In his experiments, Lombard used a “deaf-making apparatus” invented by Nobel Prize-winning Viennese physician Robert Bárány, which could produce an intense noise in one ear. Lombard measured people’s conversational speech while they were exposed to the isolated noise, and he found that their speech changed in several ways.
In “Lombard speech,” you most notably use a lot more lung power, elongate your vowels, and raise the fundamental frequency (or pitch) of your voice. You also put more emphasis on content words, which is why you scream “does your friend want a drink?” in your pal’s ear while pointing towards the bar. These speech changes are less dramatic in children than in adults, and researchers have described female Lombard speech as “more intelligible” than male Lombard speech, even though male voices change more dramatically in loud environments.
Researchers have written that the purpose of what we now call the Lombard effect “seems to be driven by both reflexive and communicative functions.” That is, you don’t just speak up to help others understand you; your boost in volume helps you self-monitor your own vocal output, too. After all, how can you know exactly what you’re saying if you can’t hear yourself saying it? Lucky for your morning-after hoarseness, science shows that speech recognition improves when that Lombard reflex kicks in, so you really are helping your friends understand you by screaming over the band. Unfortunately, you can still feel bad about the awkward selfies from the night before because the larger facial movements that accompany your vocal changes don’t actually help people understand you as much as your changes in sound do.
Lombard passed away in 1920, and his obituary read that the discovery of the Lombard effect had been of “great assistance … to the diagnosis of simulated deafness, and it is therefore in much use in medico-legal cases.” But that’s just the tip of the iceberg; today, the Lombard effect is used in hearing tests, audio-vocal integration studies, and speech therapy, and related research has been used to support architectural acoustic designs and in developing automatic speech and speaker recognition software.
The Lombard effect has also become a big deal in terms of studying animal vocal behavior. A 2003 study found that birds sing at a higher pitch in urban noise, and in 2017, Johns Hopkins University posted a video of bats demonstrating the Lombard effect. Even fish have been shown to “shout” in order to be heard over human noise. Recently, the Lombard effect was mentioned in a June 2018 study that found that animals take turns talking when they’re having conversations with each other. From studying animal speech to uncovering the evolution of vocal patterns, this is an important effect with a lot of value more than a century after its discovery. So now you understand why the guy next to you almost shouts in the subway train on his phone…
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