In the Bhagavad Gita, Krsna says:
aksharanam a-karo ’smi
Among letters, “A” is I.
“A” is a special letter, not because it comes first in our alphabet. After all, Krsna is speaking in Sanskrit to Arjuna, who is also a Sanskrit speaker. They are talking about the letter “A” in Sanskrit.
Still, when you know why the letter A is special in Sanskrit, you get to wondering if its not the same reason why the letter comes first in our alphabet and in so many (maybe all) alphabets.
Why is “A” so special?
Sanskrit is a “syllabic” language. Japanese is too. I guess most of the Asian family of languages might be. What does it mean to be “syllabic”? It means that the root sounds (the “letters”) are always single syllables in and of themselves. What is a syllable? It is a vowel sound. What then are consonants? They are con- (with) sonnance (the sound), i.e. they are sounds that appear with the vowel. They shape the beginning (or end in some languages) of the vowel. “K” for example, is a consonant. You cannot say “K” by itself. If you try to it will either comes out of your mouth as “kay” or “Kkkih.” Whatever sound you make, it will have a vowel in it. Because the main part of the sound is the vowel, and the consonant is the decoration shaping the outside of the vowel.
Of all letters, Vowels represent God.
Because no sounds can be made without vowels. All the other letters are useless without vowels. All the other consonants are like “so many zeros” and the vowel is like “a one placed in front of the zeros.” We cannot exist without God – in the same way that sound cannot exist without a vowel. Consonants do exist, but their exists is dependant upon their relationship to a vowel. In the same way, you and I really do exist, but our existence is dependant upon our relationship to God. Because God exists, we exist.
What is our role? A consonant enhances the vowel. That is our role. We are to enhance God’s reality. We are to be of service.
Of all the vowels, why “A”?
A is the first of the vowels.
Because it is, according to Sanskrit thought at least, the first, most natural sound to come out of our mouth.
The Sanskrit alphabet is beautiful because it illustrates this dependence of consonants upon vowels. In Sanskrit every syllable is a vertical line. This vertical line is the “A” sound. The consonants are curves and other shapes attached horizontally to the vertical line. Other vowels besides “A” are vertical amendments to the basic “A” vertical line.
Thus the Sanskrit alphabet itself depicts the sambandha-tattva – the truth of the relationship between the individual soul and the absolute soul.