Sha and the Three Sibilants as a Set

The sibilants are the clearest illustration of what the chart does when a group of sounds shares a manner but not a place. Rather than making a sixth row of the grid, which would have implied stops that do not exist, the tradition lists the three in order of the same forward movement through the mouth that governs the grid itself: palatal, retroflex, dental. The arrangement is consistent without being forced, and the choice tells a reader that the grid was built as a description rather than as a template to be filled. There is a further point specific to these three letters. They are among the sounds that later Indo-Aryan languages merged, so a modern speaker of several of the region's languages pronounces two or three of them identically while writing them differently, and the spelling preserves a distinction the mouth has lost.

Ranjana carries all three because it carries the Sanskrit chart, and the Sanskrit distinction was real, which is why the letters are worth recording separately even in a script whose users may not have distinguished them in speech. Recording them separately is also what keeps the atlas useful to a reader working back from a manuscript. A chart that merged the sibilants to match modern speech would leave that reader with no way to name what is actually on the page.