Mongolian Haa ᠾ

Haa writes a glottal or velar fricative and is the thirty-first letter of the alphabet. It is the last of the added letters that stands for a single sound, since the four that follow it serve clusters and syllables rather than individual consonants. Unicode encodes it at U+183E. The sound is met in words taken from other languages, chiefly Tibetan and Chinese, and is not part of the native Mongolian consonant system. Its position in the alphabet is where the additions begin to change character: up to this point the added letters supply consonants, and after it they supply larger units, which is a sign that the tradition had exhausted what could be done letter by letter and had begun to solve particular transcription problems one at a time. That progression is legible in the order itself, and it is one of the reasons the recited alphabet is worth reading as a sequence rather than as a set.

A chart that sorts the letters alphabetically by their romanisation loses it entirely, along with the seam between the inherited twenty-five and everything that follows them. As with the rest of the added group, the sound is absent from native Mongolian vocabulary, so the letter is by itself a reliable indication that a word came from somewhere else.

Every borrowed script reaches a limit. The Mongolian alphabet was taken from Old Uyghur because it worked for the Mongolian language, and it did, but the moment it was asked to write Sanskrit, Tibetan and Chinese accurately it began to run out. Adding letters solves part of the problem and not all of it. A letter can be supplied for a sound the receiving language lacks. It is harder to supply a way of writing a consonant cluster the receiving language does not permit, or a syllable structure it does not have, or a tone it does not use, because those are properties of how sounds combine rather than of the sounds themselves. The Mongolian additions show the tradition working outward from the easy cases to the hard ones: first single consonants, then a cluster sign, then two signs standing for whole syllables of Chinese.

Beyond the alphabet, the apparatus encoded in Unicode under the name Ali Gali goes further still, providing what is needed to write Sanskrit and Tibetan in full. What none of it does is turn the Mongolian alphabet into an Indian one, and the distinctions Indian phonology draws remain awkward in it. That is the honest position of any script writing a language it was not built for.