Human speech is a fascinating thing. We know that babies can learn to speak any natural language—those languages wouldn’t exist otherwise—and most conlangs are also designed to be learned and spoken. In short, any human can pronounce any human sound. There’s nothing really stopping us except our own received cultural strictures.
Now, if you’re in the business of making languages that sound “weird”, you can use this simple fact to your advantage. Many natural languages have strange sounds in their phonemic inventories. Some are shared with their close relatives, a few are more widespread, and then you have those that occasionally develop in isolation. Whatever the case, adding in some of these sounds is a surefire way to create something very different.
So this post is a brief survey of some of the odder parts of the IPA, all of which appear in one or more spoken human languages presently in existence. None of these, therefore, is truly “alien”. Indeed, we’ll start with a pair you already know.
The dental fricatives come in a matched pair, voiced /ð/ and voiceless /θ/. Both are fairly rare, as phonemes go, yet pretty much everyone in the world has heard them spoken, because they’re both present in English. To make matters worse, they’re both written the same way in our language: th. Yep, we English speakers are in the minority here, as far as language numbers go.
As far as population goes, on the other hand, it’s a different story. English has them, and so do standard Arabic, Castilian Spanish, Greek, and a few other big names. On the other hand, we’re far outnumbered by those who lack the th sounds, including such notables as German and French. (That’s the source for their stereotypical accents.) Most other languages with dental fricatives are relatively small, and quite spread out.
When people think of “weird” sounds, the clicks are usually near the top of the list. These are only common as phonemes in sub-Saharan Africa, and even there they are absent from most language families. They’re omnipresent in Khoisan, and most of the other languages where they appear seem to have borrowed them from there.
Even if you’ve never heard someone speaking Zulu or Xhosa, however, you’ve probably heard (and even used) clicks before. The chiding or disapproving “tsk” sound is, in fact, the dental click /ǀ/. The sound you make to get a horse moving (I assume, as I’ve never had to do that) is a lateral click /ǁ/. The trick, then, is learning to pronounce those in sequence with more “normal” phonemes. That’s a lot harder, and it’s one reason why nobody outside of Africa bothers to learn such languages.
Most languages with clicks will have a set of them, and there are far more than those two above. Search around for audio clips of people pronouncing them, and see how familiar they are if you forget they’re part of a “weird” language.
It’s possible to pronounce a sound that has two articulations, meaning that there are two places in the mouth where there is contact. Mostly, this is a combination of labial and velar, coming in voiceless /kp/, voiced /gb/, and nasal /ŋm/ varieties. These tend to show up in Africa (such as Igbo, whose name contains one), but they also appear in some languages of New Guinea. I’ll freely admit I don’t have the slightest idea how to pronounce them.
Implosives and ejectives
These two sets of sounds are kind of like mirrored reflections of each other. Ejectives are always voiceless, implosives always voiced, and you can have either of them at just about any point of articulation. About the only difference is that you can have ejective fricatives and affricates. What they are is hard to describe, if I’m honest, so I’ll leave that to the experts.
Both are somewhat rare as phonemes. Ejectives pop up mostly in indigenous languages of the Americas, as well as East Africa, though the Caucasus (e.g., Georgian) is full of them. Implosives tend to be found in sub-Saharan Africa, with scattered occurrences elsewhere. Either one, assuming you can pronounce it, could be a good option for oddity.
Creaky and breathy voice
These aren’t so much phonemes as they are “phonations”: different ways of pronouncing a sound. Again, I’ll refer you elsewhere for the specifics; we’re only interested here with their use in languages.
Mostly, creaky voice is closer to an intonation feature than a phonemic one, but a few languages use it as a distinction. Breathy voice (also called “murmured voice”), however, is much more common. It’s the “voiced aspirate” set in Hindi and similar languages. Either one can work for vowels or consonants, and they’re another one of those “if you can figure it out, it might be useful” things.
We haven’t even scratched the surface of strangeness in the realm of the phonetic, but this should be a good starting point for your own exploration. Too few conlangs, in my opinion, use these and other “weird” sounds to great effect. Either they ignore them entirely (fair enough, as they’re rare for a reason) or they overdo them. Used judiciously, however, they can impart an alien flavor into an otherwise “bland” language.