Tibetan Sa ས

Sa is the twenty-eighth of the thirty consonants and closes the seventh line. It writes a voiceless alveolar fricative, the s of English see, and it carries high tone as an initial in modern Lhasa speech.

Like ra and la it is one of the busiest letters in the script. It is one of the three superscripts, one of the ten suffixes, and, uniquely with the classical da, one of the two letters that may stand in the second suffix slot after another final consonant. Only ra matches it for the number of positions it can occupy.

As a superscript, the sa mgo, it is silent in modern speech and its former presence is carried by the tone of the syllable beneath it. As a suffix it closes the syllable in the ordinary way. As a second suffix it is doing something different in kind, because in that position it is very often grammar rather than lexicon.

Sa is also the voiceless counterpart of za, distinguished from it in the classical language by voicing and in modern Lhasa speech by tone, which is the same trade the whole voiced series has made.

The one office sa lacks is the prefix. That leaves ra and sa as the two letters appearing in the greatest number of positions in the script, and between them they account for a good deal of what makes a Tibetan syllable look complicated on the page and read straightforwardly once the slots are known.

A Tibetan syllable that ends in two consonants is very often ending in a grammatical marker rather than in part of a word, and the second of the two is normally sa.

The second suffix slot, the yang jug, takes only sa in the modern orthography, with the classical da drag as the other historical occupant. What sits there is typically a case particle or a verb ending fused onto the syllable it belongs to: the genitive is the most frequent, and several of the other cases and a number of verbal forms behave the same way.

For a reader this is a useful rule of thumb. Two finals means look for grammar. The word to be looked up in a dictionary is what remains when the second suffix has been taken off, and the second suffix itself is telling the reader what the word is doing in the sentence rather than what it means.

It is also one of the places where written Tibetan and spoken Tibetan diverge visibly. The second suffix has left the modern spoken language almost entirely, surviving as an effect on the vowel and the tone where it survives at all, so a syllable written with six letters may be spoken with three sounds and a pitch. The information is not lost; it has been recoded, and the writing is the record of where it used to sit.