Mongolian Oe ᠥ

Oe is the transliteration used here for the rounded front vowel, the sound usually written o with an umlaut in scholarly transcription, and it stands sixth in the alphabet. It belongs to the front class of the vowel harmony, and it is the front partner of the rounded back vowel written o. Like that vowel, it shares its written shape entirely with the letter that follows it, so that the two rounded front vowels are as indistinguishable on the page as the two rounded back vowels are. The script therefore has two rounded shapes for four rounded vowels, one shape serving the back pair and one serving the front pair, and each shape is resolved by the reader. That arrangement is more orderly than it first appears.

Because the harmony class of a word is fixed, a reader who has identified the word as a front class word already knows the rounded shape in it must be one of the front pair, so the ambiguity is halved before the reader has done any work at all. What remains is the choice within the pair, which the vocabulary settles. Unicode encodes this letter at U+1825. Alphabet charts that arrange the vowels by class rather than by recitation order place it directly beneath its back class partner, which makes the pattern easier to see than the recited sequence does.

Set out as a table rather than as a recited list, the Mongolian vowels form a small and regular system. The back series holds the open vowel a and the two rounded vowels o and u. The front series holds the open vowel e and the two rounded vowels written o and u with umlauts. The vowel i stands outside both and is neutral. Every native word draws from one series, and every suffix has a back form and a front form and presents whichever matches. The written script conveys only part of this. It marks the difference between the open vowels at the start of a word and not inside it, and it does not mark the difference between the members of either rounded pair at all.

What it does mark, and marks consistently, is enough for a reader who knows the language, because harmony makes the missing information recoverable. This is worth stating carefully rather than treating the script as merely deficient. A writing system carries some of the information in a language and leaves the rest to the reader, and where the line falls differs from script to script. Arabic and Hebrew leave most short vowels unwritten. English leaves stress unmarked. Mongolian leaves the rounded vowels undifferentiated and marks the consonant alternations that harmony governs. In each case the omission is safe because the language makes it predictable.