Tibetan Na ན

Na is the twelfth of the thirty consonants and the nasal that closes the dental line. It writes a dental nasal, made with the tip of the tongue at the teeth, and as an initial it takes low tone in modern Lhasa speech, in company with the other nasals of the recitation.

It is one of the ten suffixes and closes an enormous number of Tibetan syllables, which makes it one of the letters an eye meets most often. It is not among the five prefixes, so its orthographic work is done entirely at the end of a syllable.

That work is not merely to sit there. In the modern language a final na alters the vowel in front of it, so that the written vowel and the heard vowel differ in a way that depends on the suffix rather than on the vowel sign. A reader therefore cannot take the vowel from the sign alone and add the consonant afterwards. The syllable has to be taken whole.

Na is also, with ra, la, sa and the small a, one of the suffixes that carry grammar rather than lexicon. A great many verb endings and particles of written Tibetan end in it or consist of it, so a reader who has learnt the letter as a sound will meet it far more often as a piece of sentence structure.

With na the third of the four regular lines closes. After it the labials run the same pattern through for the fourth and last time, and the recitation then moves into the part of the alphabet that Tibetan built for itself rather than inherited.

A reader of an alphabet learns to convert letters into sounds in order and assemble the result. That method fails on Tibetan, and understanding why is most of what separates decoding the script from reading it.

Four things get in the way. The first letter written may be a prefix, contributing no sound. The letter above the root may be a superscript, likewise silent, and both of them may instead be affecting the tone of the whole syllable rather than adding anything of their own. The vowel is written on the root and is then modified by whatever suffix follows, so it cannot be settled until the end of the syllable has been reached. And the tone, which in the modern language carries much of the distinction between words, is a property of the entire stack computed from several of its parts at once.

The consequence is that a Tibetan syllable is read as a unit. An experienced reader takes in the stack, identifies the root letter, and produces a syllable whose sound and pitch follow from the whole arrangement. The tsheg, the small raised dot between syllables, is what makes this possible at speed: it says where one unit ends, so the eye is never in doubt about how much to take in at once.

None of this makes the script irregular. The rules are consistent and there are not many of them. They simply operate on the syllable rather than on the letter.