◊       Graduating to vāk or speech from the level of akśhar or letters the Vedas say in Brihadāraṇyaka Upanishad I.6.1 :-

trayam vā idam nāma rūpam karma tesām nāmnām
vāg+iti+etat+esām + uktham +atah+hi   sarvāni
nāmāni+uttisthanti . etad esām sāma+etat+hi
sarvaih+nāmabhih   samam +etad+esām
brahma+etad+hi sarvānI nāmāni bibharti.

Coupled with Br. I.4.7 on Pg. 691 of the above reference this shlöka says :

All that is manifest in the visible universe is covered by the triad viz. nāma – rūpa – karma i.e. name/number, shape/form and action/work. Of these as regards names, speech is the source, for from it all names arise. It is their common feature ; for vāni or the spoken word is the foundation of all names. This speech can be likened to the Brahman, the Unknown, for from our memory of learnt speech the known names filter into our consciousness, ultimately they are nurtured back into the realm of vāni or speech as we speak about things.

Now let us go to the alphabet itself…

The Sanskrit Alphabet