Mongolian Zhi ᡁ

Zhi is the thirty-fourth letter of the alphabet and stands for a syllable met in words taken from Chinese, for which the alphabet carries a transcription letter rather than a combination of its own signs. Unicode encodes it at U+1841. A letter that writes a syllable is not an alphabetic device at all, and its presence at the end of the Mongolian alphabet marks the point at which the alphabetic principle was set aside for a particular practical purpose. The Chinese syllable in question has no comfortable spelling in Mongolian letters, since its initial consonant and its vowel both fall outside what the script was built to write, and combining approximations would have produced a form no reader could recognise as the original.

A single agreed sign was the more useful answer. The letter that follows it does the same job for another Chinese syllable, and the two close the alphabet together. They are the last additions in the recited order and the furthest from the inherited core, which is exactly where a device of this kind belongs. Neither letter is common, since each serves one syllable of one foreign language, and both belong to the layer of the alphabet that describes Mongolian's neighbours rather than Mongolian itself.

Chinese is difficult to write in any alphabet, and the difficulty is structural rather than a matter of a few awkward sounds. A Chinese syllable is a tightly constrained unit, with a limited set of initials, a limited set of finals and a tone, and the syllable rather than the individual sound is what speakers and writers treat as basic. An alphabet built for a language with different syllable shapes and no tones cannot represent that inventory efficiently: it will spell some syllables in ways no Chinese reader would accept, fail to distinguish others, and record no tone at all.

Transcription systems for Chinese have taken various routes around this, and the route the Mongolian alphabet took for a small number of frequent syllables was to supply a sign for the whole syllable rather than spell it. That is the same instinct that produced Japanese kana from Chinese characters, arrived at from the opposite direction and on a very much smaller scale. Two letters is not a syllabary, and it was never meant to be one. It is a targeted repair to an alphabet in the few places where the alphabet was failing most visibly, and it leaves every other Chinese syllable to be spelled out with whatever the alphabet can manage.