In plain words
Many great souls understood the supreme secrets of the world's beauty in the sky of the heart and, for the welfare of the world, proclaimed their experience to the world as the splendour of speech: that is Vidyā. What is foremost in the Veda is sound, nāda. This nāda is to be heard and enjoyed, not to be criticised. That is why it came to be called “Śruti”, what is heard. What draws the inner experience of the Ātma out by hearing alone and gives Ānanda that delights from the first moment is “Vidyā”.