Mongolian Lha: The Tibetan Voiceless Lateral

Lha is the thirty-third letter of the alphabet and writes the voiceless lateral of Tibetan, the sound that opens the Tibetan word for a god. Mongolian does not have it. Unicode encodes the letter at U+1840. It is the clearest single case in the alphabet of a letter added for one language's sake, and the word it is named for tells you which language and which subject matter: the transcription of Tibetan Buddhist vocabulary, in which divine and honorific terms built on that word are constant. A voiceless lateral is an unusual sound outside a handful of language families, and Tibetan is the source of nearly every Mongolian word containing one. As with the other added letters, the shape is an adaptation of a letter already present, in this case the native lateral.

The letter is a compact illustration of how a religious tradition reshapes a writing system: not by changing how the language is written, but by adding what is needed at the edges so that the vocabulary of the tradition can be set down correctly in the tradition's own terms. It stands thirty-third in the recited order, among the last of the additions and immediately before the two letters that serve Chinese syllables. Its presence also settles a question a reader might otherwise ask about the added group, which is whether the ten letters were supplied for one language or for several: this one is Tibetan, two are Chinese, and the aspirate serves Sanskrit through Tibetan spelling.