The following attempt is to capture whatever has been beautifully explained by Sri Bannanje Govindacharya in one of his Kannada pravachanas.
It is well accepted that the famous Brahma Gayatri mantra has 24 aksharas in them. But upon splitting the words in the mantra into their aksharas, we find the following:
1 तत् 2 स 3 वि 4 तृ 5 व 6 रे 7 ण्यं 8 भर् 9 गः 10 दे 11 व 12 स्य 13 धी 14 म 15 हि 16 धि 17 यः 18 यः 19 नः 20 प्र 21 चो 22 द 23 यात्
As we can see there seem to be only 23 letters in the Gayatri!
The well known answer to this is of course that the 7th akshara ण्यं is pronounced as णि and यं thereby introducing an additional syllable and hence the total amounts to 24.
The Gayatri mantra, in the Vaishnava sampradayas, is well known as the mantra of Sri Vishnu. And each syllable in this mantra is represented by one Roopa or form of Sri Hari. In his classic work – Tantrasara Sangraha – Sriman Madhwacharya says the following about the Gayatri mantra.
चतुर्विम्शन्मूर्तयोsस्याः कथिता वर्णदेवताः | तद्भेदः पौरुषं सूक्तं वेदाः पुरुषसूक्तगाः || 1 – 15 ||
“The twenty four forms of Sri Hari are the Devatas for the Varnas (of the Gayatri). From the three divisions (of eight syllables each) of the Gayatri, the Purusha Sukta manifested. From the Purusha Sukta manifested the Vedas”
Thus, the well known Chaturvimshati Rupas of Sri Hari are verily the Devatas of the 24 Varnas of the Gayatri.
Does this mapping of the 24 forms of Sri Hari give us an indication that the pronunciation of the word वरेण्यं as वरेणियं is correct? Let us see.
The Varnas and the corresponding forms are as follows:
तत् – Keshava स – Narayana वि – Madhava तृ – Govinda व – Vishnu रे – Madhusudana णि – Trivikrama यं – Vamana भर् – Sridhara गः – Hrishikesha दे – Padmanabha व – Damodara स्य – Sankarshana धी – Vasudeva म – Pradyumna हि – Aniruddha धि – Purushottama यः – Adhokshaja यः – Narasimha नः – Achyuta प्र – Janardana चो – Upendra द – Hari यात् – Krishna
When we look at this mapping, we find one extremely interesting placement. For the syllable णि the Devata is Trivikrama. For the syllable यं the Devata is Vamana. However, Trivikrama and Vamana are the names of the very same Avatara of Paramatma!
When Sri Vishnu entered Bali’s Yajna, he was Vamana. When he accepted Daana from Bali, he was Trivikrama. Hence Trivikrama and Vamana are, at the same time, different and same forms!
This fact is reflected in the usage of the syllables also. While writing, the two syllables get combined into ण्यं and while pronouncing they are used as णि and यं. And of course, it is the pronunciation that matters when it comes to Vedic mantras.
Hence, the Vedic prayoga of pronouncing them separately is in complete alignment with the Rupas of Sri Hari that correspond to each Varna of the great mantra.