Each individual language has a few number of sound units (phonemes) and research suggests geography may affect which phoneme's usage become commonplace.
The ejective consonant (e.g. "P" or "K") phoneme exists in ~20% of the languages. Of 500+ languages studied, research shows that languages spoken at higher elevations were more likely to use ejective consonants. This may be because lower air pressure eases the burst of air characteristic of this phoneme.
