Tibetan Wa ཝ

Wa is the twentieth of the thirty consonants and the odd member of the recitation. It writes a labial approximant, the w of English wet, and it stands at the end of the fifth line after the three affricates, which is the position an added letter would naturally take.

It is also one of the four subscripts. Written beneath a root letter it is called the wa zur, and in that position it can sit under a large number of letters. In most modern pronunciation it makes no audible difference to the syllable at all, so a stack containing it is spoken as though it were not there, and its effect is on the spelling and the identity of the word rather than on the sound.

That double existence is why the grammarians do not fully agree about it. Some accounts treat wa as a letter of the alphabet that also happens to serve as a subscript, in the way that ya, ra and la do. Others treat it as a subjoined form promoted to letterhood, a Tibetan device rather than an inherited letter, and point to its position at the end of a line as the mark of an addition. The atlas records the correspondence to the Indic labial semivowel as debated for that reason, rather than asserting a descent that is not agreed.

Whichever account is preferred, the practical facts are not in dispute. Wa is recited as the twentieth letter, it can head a syllable, and it can be subjoined beneath one. The disagreement is about where it came from, and it changes nothing a reader has to do.

Beneath the root letter of a Tibetan syllable there may be a subscript, the btags, and four letters may take that position: ya, ra, la and wa. No others.

Each behaves differently, and none of them simply adds its own sound. Subjoined ya changes the letter above it, so that in modern Lhasa speech a labial with a ya beneath it is heard as a palatal. Subjoined ra likewise alters the consonant above it rather than being pronounced as an r. Subjoined la produces a value of its own that has little to do with either letter. Subjoined wa is generally inaudible.

The subscript is one of four positions in a syllable stack, and the positions are fixed: superscript above, root at the centre, subscript below, vowel sign above or below the whole, with a prefix before and a suffix or two after. A full stack can therefore run to six or seven written elements and is still one syllable, closed by a single tsheg.

Learning the four subscripts is not optional even for a reader who never writes, because they change what a stack sounds like and because they affect where a word is filed in a dictionary. The order of comparison in Tibetan lexicographic sorting runs root letter, then superscript, then subscript, then vowel, then suffix, so the subscript is a sorting key as well as a piece of pronunciation.