If you observe the Sanskritized words in regional Indian languages, you can see specific modifications to word endings, which can usually identify the speaker's state orientation. Tamilians say rAman or kriShNA with a "an"-ending or elongation of a. In Telugu it becomes rAmudu. North Indians say it as rAm, with the last "a" disappearing altogether. Bengalis prounounce "a" with a tendency towards "o", so pArtha becomes pArtho, ajay becomes ajoy. But what is the correct pronounciation of अ itself in Sanskrita? What is the effort put to say अ ?
अथ शब्दानुशासनम् । This is how Panini begins his aShTaadhyaayI. His work revolves around word formations. Panini's work relies on earlier literature of Vedanga called शिक्ष or प्रतिशाख्य that deals with phonetics. Two factors influence production of each varNa: aasya (place of sound) आस्य and prayatna प्रयत्न (effort). Prayatna in-turn is classified into aabhyantara-prayatna आभ्यन्तर-प्रयत्न (effort during origination of sound) and baahya-prayatna (effort during ending of sound). aahbyantara prayatna is of 5 varieties (स्पृष्ट: touched, इषत्-स्पृष्ट: somewhat touched, विवृत: open, इषत्-विवृत: somewhat open and संवृत). baahya prayatna is of 11 varieties, we will see those some other time.
Consonants are classified as "touched", because the toungue touches other parts of the mouth during pronunciation. All vowels are classified as vivRuta - "open" because the mouth is open during pronunciation. That is, all vowels except "a". "a" should be pronounced with the same time taken to prounounce the a in "cut", "but", but not as in "fast", "mask". This effort is called saMvRuta. It singularly belongs to the varNa अ.
If you have the Vaman Shivaram Apte's Sanskrit-English dictionary, check out the very first meaning of "a", which itself is the very first entry.
Meanwhile let us look at a sloka.
याम: श्रयति याम् धत्ते यैन यात्याय याच्च या ।
याऽस्य मानाय यै वान्या सा मामवतु पादुका ॥
That which viShNu takes up, that which bears viShNu on itself, that which moves about because of viShNu, that which is for viShNu, that which originated from viShNu for his purpose, that which secures respectability for viShNu, that which is attainable to us at viShNu, may that pAduka protect me.
Notice in the sloka that there is not a single mention of the word viShNu or even any other name of the Lord, yet the sloka seems to refer the Lord continuously. Is the word viShNu hidden? Really? Hmm...
The key to any sloka is in splitting the sandhi-s correctly. Slokas like this need commentaries. Let's first split the sloka and then analyse.
याम् अ: श्रयति या अम् धत्ते या एन याति आय या आत् च या ।
या अस्य मानाय या-ए वान्या सा माम् अवतु पादुका ॥
Once we split the sandhi, the sloka is pretty straight-forward in meaning. All the yaa's refer to "that which" which is qualified later by "saa paaduka". Sri Vedanta Desikan, the creator of this sloka, plays on the letter, actually a shabda in this context, अ and conjugates different vibhakti-s on it. Sanskrita students may remember the vibhakti-s of अकारान्त पुंलिङ्ग एकवचन राम शब्द: as राम:, रामम्, रामेन, रमाय, रामात्, रामस्य, रामे etc. Now instead of राम शब्द, conjugate just for ’अ’ शब्द. The vibhakti-s are अ:, अं, एन, आय, आत्, अस्य, ऐ ! Since we know that अ means viShNu, the conjugations simply mean viShNu (subject), viShNu (object), by viShNu, for viShNu, from viShNu, of viShNu, in viShNu respectively.
Meanwhile, vishnu sahasranama mentions a thousand names of Vishnu. So is अ one of the names there? You betcha! The 25th sloka says:
आवर्तनो निवृत्तात्मा संवृत: संप्रमर्दन: ।
अह: संवर्तको वह्नि: अनिलो धरणीधर: ॥
From this we can extrapolate the meaning of saMvRuta: as one whose prounounciation is that of अ who is viShNu !
So much for a simple अ ! Those who are interested, may pursue why paaNini ends his ashtaadhyaayI with a mind-blowing sUtra with just two characters:
अ अ ।