Pahalvi Texts (Vol. 4)

Book Pahlavi is a smoother script in which letters are joined to each other and often form complicated ligatures. Book Pahlavi was the most common form of the script, with only 12 or 13 graphemes (13 when including aleph) representing 24 sounds. The formal coalescence of originally different letters caused ambiguity, and the letters became even less distinct when they formed part of a ligature. In its later forms, attempts were made to improve the consonantary and reduce ambiguity through diacritic marks. Book Pahlavi continued to be in common use until about AD 900. After that date, Pahlavi was preserved only by the Zoroastrian clergy.