Mongolian Chi: The Thirty-Fifth Letter

Chi is the thirty-fifth and last letter of the traditional Mongolian alphabet. Like the letter before it, it stands for a syllable met in words taken from Chinese rather than for a single sound, and it exists because the alphabet could not spell that syllable out of its own letters. Unicode encodes it at U+1842, the last of the alphabet's letters in the Mongolian block, which runs from U+1800 to U+18AF and holds a good deal besides. The alphabet ends where it does for a reason that is visible in the order. It opens with the seven vowels of the native system, continues through the native consonants to the labial glide at the twenty-fifth position, and then adds ten letters for foreign sounds, moving from single consonants through a cluster to two whole syllables.

The last letter is therefore the furthest point of a long adaptation, and reciting the alphabet from the first letter to this one is reciting its history in order. What lies beyond it in the same Unicode block is not more of this alphabet: it is the Ali Gali apparatus for Sanskrit and Tibetan, and the letters of Todo, Sibe and Manchu, which are separate writing systems built on the same inherited shapes and no part of the thirty-five counted here.