Actually the
Arapaho language spoken by some (250 - 1.000 people
) Native Americans in Wyoming and Oklahoma doesn't have an A sound (yes I know that sounds very weird since the name of the language in English literally has 3 A's in it). But they call the language Hinóno'eitíít, Arapaho comes from the name which was given to the tribes living in the area by European settlers, although where that word comes from isn't exactly certain.
According to Wikipedia ~98% of languages have open vowels (vowels where the tongue is positioned as far from the roof of the mouth as possible) like [a], [ɶ], [ɑ], [ɒ] (the ones that have dedicated symbols in IPA) and [ä]/[ɐ̞] and [ɒ̈] (which don't have dedicated symbols in IPA) although I can't seem to find any examples of the other ~2% of languages that don't have these.
Since many languages have also existed that we haven't yet, or might not ever discover, we're not really able to say anything about those languages, maybe those also didn't have any A sounds and we will just never know.
As a side note, some languages like the
Kabardian language spoken in the Northern Caucasus or the
Arrernte language have a so-called
vertical vowel system, which means that even though in spoken language you may hear many different vowels, these vowels are in essence only variations of a couple of vowels (the two examples I listed are considered to only have 2 vowels). Kabardian was even considered by some to have no vowels at all at some point, so words were considered to just be long strings of consonants in which you heard vowels because they would be unpronouncable without them, but where the vowel sounds would actually be part of the consonant letters. This, however, isn't the interpretation of modern linguists have anymore.
yes, i am aware that i am a nerd
Edit: There are also languages which have considerably more vowels than others, like
Hamont-Achel Limburgisht, which has 22 (!)
monophtong phonomenes (vowels consisting of a single letter) and 13 (!)
diphtong phonomenes (which are made by combining multiple vowels together). This means that the language has more monophtongs than consonants. The language is also unique in that it has a distinction between front, central and back open vowels, as one of the only languages in the world. As a comparison, most English dialects only have ~12 monophtongs and ~8 diphtongs.