It was about the Word, the primal sound. Sri Aurobindo speaks of it in Savitri: the essence of the Word and how it will express itself, how it will bring in the possibility of a supramental expression that will take the place of languages.... I began by speaking to him about the different languages, their limitations and possibilities; and I warned him against the deformations imposed on languages with the idea of making them a more flexible means of expressing something else. I told him how completely ridiculous it all was, and that it didn't correspond at all to the truth. Then little by little I began ascending to the Origin. So yesterday again, I had this same experience: a whole world of knowledge, of consciousness and of CERTAINTY - precluding the least possibility of contradiction, discussion, or opposition; the possibility DOES NOT EXIST, it doesn't exist. And the mind was absolutely silent and immobile, listening with obvious pleasure because these things had never before come into my consciousness; I had never been concerned with them in that way. It was completely new - not new in principle but completely new in action.

The experiences are multiplying.

A sound that can bring in the supramental Force?
Yes. While speaking, you see, I went back to the origin of sound (Sri Aurobindo describes it very clearly in Savitri: the origin of sound, the moment when what we called 'the Word' becomes a sound). So I had a kind of perception of the essential sound before it becomes a material sound. And I said, 'When this essential sound becomes a material sound, it will give birth to the new expression which will express the supramental world.' I had the experience itself at that moment, it came directly. I spoke in English and Sri Aurobindo was concretely, almost palpably, present.

Now it has gone away.

page 48-49 , Mother's Agenda , volume 2 , 27th Jan. 1961