High Sith was a script that stemmed from early hieroglyphics utilized by the Sith, created chiefly for ecclesiastical uses.
Most Sith manuscripts that have been found were written in High Sith, which was more ornate than its mundane counterpart, the Common Sith alphabet. Among them was Freedon Nadd's Sith spellbook.
Another Sith script, Massassi, was in use by the warrior class of the Sith species, and appeared etched on temple walls on Yavin 4; xenographologists discovered that the Massassi alphabet had ties to the simplified component of High Sith writing.