There are some pretty weird sounds among all the possible ones that humans can make with their mouths, but what are the most unusual sounds in the world’s languages?
First we need to ask, what is “unusual”? Is a sound unusual if it’s only present in very few languages? Or if it occurs in languages that only have a few speakers? But what about a sound that’s unusual in one language, but in another language it pops up all the time? Let’s take a look at some different examples to get an idea of the most unusual sounds in the world.
Note: I’ll be using the International Phonetic Alphabet and other linguistics terms to talk about these sounds because most of them don’t occur in English. Don’t worry, though, we’ll break everything down so it’s easy to understand.
The TH-Sound (Dental Fricatives)
If you’re a native English speaker, this may come as a shock to you, but the TH-sound (A.K.A. dental fricative) we use every day is actually pretty rare.
There are actually two sounds that count as dental fricatives: /θ/ and /ð/. They are produced by putting the tip of your tongue behind or right underneath your top teeth and pushing air through your mouth. /θ/ is voiceless, meaning there’s no vibration accompanying from your vocal cords, while /ð/ is voiced. Both occur in English, which is one of the most widely spoken languages in the world, but they don’t pop up in many other languages.
The voiceless dental fricative /θ/ is present in several languages which have relatively large numbers of speakers, such as European Spanish, Modern Greek, Swahili and Burmese. It also occurs in some languages that have significantly fewer speakers like Albanian, Icelandic and several Amerindian, African and Polynesian languages.
That said, this is still a very rare sound across the world’s languages, if only because non-native speakers have a real difficulty making this sound. For one, humans don’t always have all their teeth in old age, and children acquiring a language don’t have all their teeth either — but teeth are essential to produce it! Because of this, several language varieties with this sound are actually in the process of eliminating it.
Lateral Fricatives
This next unusual sound doesn’t exist in English, so it’ll be a bit harder to explain. Lateral fricatives are two sounds that are represented by the IPA notations /ɬ/ and /ɮ/. They are produced by putting the front part of your tongue on the alveolar ridge (behind the teeth), flexing the sides of your tongue up and pushing air out of your mouth with friction so that air exits through the openings on both sides of your tongue. (If that was hard to wrap your head around, watch this video for a better idea.)
Like with the dental fricatives, /ɬ/ is voiceless, meaning there is no vibration from the vocal cords, while /ɮ/ is voiced. The voiceless variant is slightly more common, and is found most famously in Welsh. You might also be familiar with it if you speak an American indigenous language like Navajo, Creek, and some varieties of Cherokee.
Unfortunately, all of these languages are relatively small in terms of numbers of speakers. Plus, the other languages where /ɬ/ is found, such as Zulu (spoken in South Africa) and Dahalo (spoken on coastal Kenya) also do not have many speakers. Looking at the number of living speakers, this makes lateral fricatives quite an unusual sound.
The Swedish SJ-Sound
This sound is so unique that it only occurs in Swedish. In fact, Swedish is only spoken by 10 million people, meaning that this could easily be considered one of the “most unusual” sounds in the world on two accounts.
The SJ-sound has several different pronunciations depending on the dialect of Swedish, but what is between all of them is that it’s a voiceless fricative (meaning it’s produced by expelling air from your mouth and without any vocal cord vibration), and is accompanied by a noticeable labialization (A.K.A. rounded lips).
In IPA, it’s transcribed with the symbol /ɧ/, and is called the voiceless postalveolo-velar fricative, among other terms. Some phoneticians say the simplest description of this sound is that it’s the /ʃ/ (as in “shoe”) and /x/ (as in Scottish “loch” or German lachen) sounds made simultaneously, with very rounded lips.
In Swedish this sound is actually very common, so if you were to ask a Swede if this was an unusual sound, they’d probably disagree with you.
Non-Pulmonic Consonants
The largest group of uncommon sounds among the world’s languages are non-pulmonic consonants — but what are they? While all other sounds are pulmonic, meaning they’re produced by pushing air out of the lungs and changing the airstream on its way out, non-pulmonic consonants do not use an airstream from the lungs.
But how can we make speech sounds without air from our lungs? Well, the most well recognized subgroup of these sounds are clicks. In English we use clicks to express disapproval (seen in written form as “tut tut” in British English and “tsk tsk” in American English), or the sound used to spur on a horse (usually written as “tchick”).
There are several languages which use clicks as regular phonemes, meaning sounds that can contrast with, for example, a /p/ or /s/ sound to make a difference in meaning. All of the languages which use clicks phonemically are found in Africa, mostly concentrated in Southern Africa and the majority of those are in the Bantu language family (though there are some exceptions).
One of the most well-known click languages is Xhosa, one of the official languages of South Africa and whose name begins with lateral click. It has 18 other distinct click sounds in its inventory, which might seem like a lot — until you compare it to other click languages. For example, Taa, a minority language spoken in Botswana and Namibia, has 83 distinct clicks sounds!
So can we say that click sounds are unusual? They’re used by speakers across the globe, but only a few languages use them as consonants. So in fact, clicks are quite common, they’re just not thought of by most people outside of Southern Africa as language sounds. It’s all a matter of perspective!