Mongolian Sa: The Voiceless Sibilant

Sa writes the voiceless sibilant, the sound spelled s in English, and it is the sixteenth letter of the alphabet. It is native, frequent and distinctly written. Unicode encodes it at U+1830. Its historical interest is that it is one of the letters whose descent from the Aramaic abjad is straightforward and uncontested: the sign for s passed from Aramaic into Sogdian, from Sogdian into Old Uyghur, and from Old Uyghur into Mongolian, keeping its sound value throughout. A great many borrowed alphabets lose that kind of continuity, because the sound system of each new language redistributes the letters, and the sibilants are usually among the first to be reassigned. Mongolian kept both the s and the sh of its source inventory and kept them apart, which is one reason the correspondence between the two alphabets is still easy to see.

The letter also plays a large part in the religious vocabulary, since Sanskrit and Tibetan terms brought into Mongolian Buddhist writing are full of sibilants, and it was the inadequacy of two sibilant letters for the three that Sanskrit distinguishes that helped drive the development of the extended transcription signs. The letter carries no harmony alternation and no shared shape, which puts it among the small group of Mongolian letters a learner can read with confidence from the first week, and which makes it a useful landmark when working out the more ambiguous shapes standing beside it on the spine.