Pattern Before Frequency

The Brahmi order gives this letter the same standing as the commonest consonant in the language, and the reason is the shape of the analysis rather than any judgment about usefulness. Each of the five classes carries four stops and a nasal because voice and aspiration vary independently at each of five points of articulation, and a table built that way generates every combination whether or not the language fills it. The tradition kept the combinations it did not need, and taught them in sequence with the rest.

That decision has a practical justification and the Indian phoneticians were explicit about it. A complete pattern can be recited, and a recitation is how the order was carried for centuries before anyone had cause to write it out as a list. A table with a gap in it has to be memorised as a list of exceptions, which is a far harder thing to transmit accurately across generations of oral teaching. The five by five arrangement is therefore a mnemonic as much as an analysis, and its regularity is the reason the alphabets of South Asia still agree with one another on the sequence of their letters after two thousand years of independent development in a dozen different regions.

It is worth saying plainly that this is unusual. Most alphabets in the world preserve an order inherited from an earlier script for no reason connected with the sounds, and their sequences cannot be predicted from anything about the language. The Indian order can be reconstructed from the analysis alone by anyone who knows the features, which is why a learner can be taught the principle and then derive the list rather than memorising it as an arbitrary string. That is a different kind of object from an alphabet, and it is the reason the sequence has proved so durable.