A correspondent writes: “I use an ingressive sound when I say ja in Norwegian. I don’t have a sense of how common this is across the spectrum of languages, but it is absent in the other ones I speak.” He included a link to this The Local piece about the phenomenon in Swedish:
Northern Swedes have the unique ability to give their assent with a simple inhalation – a sharp sound of apparent shock, often mistaken by foreigners as a gasp of surprise. Perhaps not strong enough to suck up dust, but strong enough to shock a foreigner.
In fact, many a visitor to Sweden can remember the first time they came across the “northern vacuum”, a short, sharp noise pronounced like “shhh” but while breathing inwards. Let’s spell it “Shoop”. [...]
According to [Linköping University's Professor of Phonetics Robert] Eklund, the phenomenon is called “ingressive speech” or “phonation”.
“Ingressive speech is when people produce language – sounds, single words, or even entire phrases – while breathing in,” he explains.
For Swedes, “shoop” is reserved exclusively for “yes”, and Eklund estimates that Swedes make the sound once for every ten yesses they say.
Eklund has collected data on the phenomena from around the world, concluding that the sound is not so unique, and is even found among donkeys and purring cheetahs.
In the human race, ingressive speech is often cited by proud Swedes as unique to Sweden, especially to northern Sweden, but Eklund’s research suggests otherwise.
“In Norway they say it only happens in Norway,” Eklund laughs.
In fact, ingressive speech takes place in every continent, in as many as fifty languages. In Canada and the US, some people even use it in the same way as the Swedes.
“But in the Philippines and Greece boys used it when flirting with girls to disguise it from their fathers,” says Eklund.
Interesting stuff, and I agreed that it was worth a post (thanks, Jeff!).