My Psammothermophonetic Theory originates from a simple observation in comparative linguistics:
As you progress from warmer to colder climates,
the proportion between vowels and consonants shifts in favour of the latter in the languages there spoken: consider for instance Neolatin, Greek, Chinese, Japanese and Polynesian languages as opposed to Germanic, Scandinavian and Slavic languages.
This requires an explanation, and it can only be reached
considering the different way in which sounds are articulated: since vowels are pronounced
with a more open mouth than consonants, it is obvious that this results in a less than pleasant experience when it is cold outside.
Thus originates the thermophonetic part of my theory, which however was severely shaken when I started studying Arabic, a language from an undeniably hot
country where vowels are officially only 3 (a,u,i).
Since you cannot blame the cold in a place like the Arabic Peninsula (except at night, when not much conversation occurs, anyway), what other cause can one find? After many a sleepless night, I eventually solved the problem: SAND (ò psàmmos in Greek) ! Getting mouthfuls of sand is undeniably inconvenient, therefore Semitic people have wisely limited the risk by reducing the number of vowels in their languages.
Q.E.D. (Quod Erat Demostrandum)
(I must honestly confess that my theory has some difficulty in accomodating languages of the Inuit type, but probably Eskimos talk much less in the open than they do in the warmth of their igloos).