Mongolian Zra and the Clusters a Language Will Not Allow

Every language restricts which consonants may stand together and where. English permits an initial three consonant cluster in street and forbids one in the shape of the Russian word for hello. Mongolian is comparatively restrictive, with a native word structure built around alternating consonants and vowels and little tolerance for clusters, especially at the start of a word. A borrowed word arriving with a forbidden cluster is normally repaired, by inserting a vowel, by dropping a consonant, or by replacing the whole sequence with something the language allows, and older layers of loanwords in Mongolian show exactly those repairs. Writing is a different matter.

A learned tradition transcribing a Sanskrit or Tibetan term wants the original shape on the page whether or not any reader will pronounce it, and that requires the script to write what the language forbids. The cluster letter is one answer to that, and the extended apparatus for Sanskrit and Tibetan is a much larger one. The tension between what a language permits and what its learned writing records is common wherever a scriptural vocabulary crosses a language boundary, and it is one of the things that makes a religious script diverge from an everyday one.