Why would a language created by humans lack the /j/ semivowel, and even the /i/ vowel?

Question

What I mean is the sound /j/ (as in English yellow and French hyène 'hyena') is the most common semivowel around the world. This phoneme is highly conserved in Indo-European languages (this language family include Italic languages like French and Italian, Germanic languages like English and Dutch, Slavic languages like Russian and Polish, etc.).

Also, the sound /i/ (as in English hippie) (the word hippie is also used in French) in one of the most, if not the most common vowel around the world.

Both phonemes are almost universal, as is the consonant /m/ (as in English mother, and French mère 'mother').

I know many languages that lack the semivowel /w/ like Albanian, Armenian, Greek, and Russian (the semivowel /w/ is found in both English as in world, and French as in oiseau 'bird').

In the universe I am creating, there is a species named ogres (their scientific name is Homo corpulentus 'obese human', so they are still humans, just not Homo sapiens). In the most spoken language used by ogres, there are five basic vowels:

/a/ (as in French arbre 'tree'), the sound corresponding to the /a/ in English gasp;
/ɔ/ (as in English oar, and French ordinateur 'computer');
/u/ (as in English cool, and French ouvrier 'worker');
/y/ (as in French univers 'universe');
and the sound corresponding to French /ø/ (as in euphémisme 'euphemism').
There are no diphthongs in the most spoken language used by ogres, but there are long vowels, and two nasal vowels: /ɑ̃/ as in French antagoniste 'antagonist', and /ɔ̃/ as in French mouton 'sheep; mutton'.

Also, the most spoken language used by ogres has both the semivowel /w/, and the semivowel corresponding to the /ɥ/ in French fruit 'fruit'.

So, I wonder why would a language created by mammals from the Homo genus lack the semivowel /j/, and even the vowel /i/.

Answer 1

One simple way to make this happen would be to make ogres unable to raise their tongues to the roof of their mouths.
[i] and [j] both require that, so they are now impossible for ogres.
Most of the other sounds you mentioned ([a], [o], [u], [ø], [ɑ̃], [ɔ̃] and [w], if I counted correctly) do not use a raised tongue and are still possible.
The only problem would be [y], [ɥ]. (That second one is the IPA symbol for the labio-palatal approximant, the French ui.) I propose that you could open [ø] to the open front vowel [œ] and lower [y] to the now-unused mid front vowel [ø]. On the other hand, I admit, I don't know how to best take care of [ɥ] here.

Another way would be to just say that the ogres can't raise their tongues without also rounding their lips, that might be biologically feasible, and it would allow [y] and [ɥ], while ruling out [i] and [j]. (Rounded [j͗] would still be possible.)

On the very other hand, if you're just wondering whether it could naturally happen: Probably. According to Phoible, 92% of human languages have [i] and 90% have [j], so it stands to reason that at least about 1%, i.e. one or two dozen (!) languages, have neither. Lacking both of them is therefore still naturalistic.

Answer 2

Lacking /j/ and [j] is entirely plausible, no explanation needed. Attic Greek, for example, lost [j] and did just fine without it for hundreds of years.

Lacking [i] is harder to explain. There's a strong tendency for vowels to expand to fill the available space, metaphorically speaking. Human languages are under a lot of evolutionary pressure to convey as much information as possible without exceeding the limits of our auditory systems, so if there's a way to convey more information without causing problems for processing, languages will use it.

What this means is, since [i] is very easy for humans to hear, human languages tend to make use of it in one way or another. Even if a language doesn't have /i/, [i] will tend to appear as an allophone of something else. This is why it appears in so many different languages. For example, Ubykh is generally analyzed as having only two vowel phonemes, a high one and a low one, but that high one will still surface as [i] to convey more information about the surrounding consonants.

If you don't want any [i] sound in your language, while still being naturalistic, you'll probably want to invoke some physical reason. The speakers of your language, from the sound of it, are biologically different from modern humans. You could simply make [i] difficult for them to produce or distinguish, for various reasons—Richard suggests production difficulties but you could also invoke some perception difficulties. The human ear is tuned to be more sensitive to some frequencies than others, and perhaps the large gap between the formants in [i] is not as distinctive to them as it is to us.