Swedish Phonology
Swedish Pulmonic Ingressives
In northern Sweden, the word yes is widely communicated by a sound that’s reminiscent of someone sucking through a straw. It’s called the pulmonic ingressive. Linguist Robert Eklund calls this a neglected universal, meaning that it’s only recently been recognized as a sound that’s part of many languages around the world, even though it’s been around for a while. In one study, Swedes talking on the phone used ingressive speech when they thought they were speaking with a human, but not when they thought they were conveying the same information to a computer. This is part of a complete episode.
Source: https://www.waywordradio.org/swedish-pulmonic-ingressives/
Ingressive speech
Ingressive speech sounds are produced while the speaker breathes in, in contrast to most speech sounds, which are produced as the speaker breathes out. The air that is used to voice the speech is drawn in rather than pushed out. Ingressive speech can be glottalic, velaric, or pulmonic.
Occurrence
Ingressive sounds occur in many languages. Despite being a common phenomenon, they are frequently associated with Scandinavian languages. Most words that are subject to ingressive speech are feedback words (“yes, no”) or very short or primal (a cry of pain or sobbing). It sometimes occurs in rapid counting to maintain a steady airflow throughout a long series of unbroken sounds. It is also very common in animals, frogs, dogs, and cats (purring). In English, ingressive sounds include when one says “Huh!” (a gasping sound) to express surprise or “Sss” (an inward hiss) to express empathy when another is hurt.
Tsou and Damin have both been claimed to possess an ingressive phoneme. Neither claim has been validated to date however, and the Tsou claim has been nearly disproved. There are claims of Tohono O’odham women speaking entirely ingressively.[4]
There are examples of ingressive sounds that belong to paralanguage. Japanese has what has been described an apicoprepalatal fricative approximant. This sound is similar to an inbreathed [s]. It is used as a response to statements that are upsetting or as a sign of deference. Japanese-speakers also use an ingressive bilateral bidental friction as a “pre-turn opening in conversation” or to begin a prayer.[5][6]