Diacritics and the Perso-Arabic script

In this paper, I will examine diacritics in order to show that the graphemics of a language is in principle dependent on its phonological structure. I distinguish three types of diacritics: (1) Those that represent distinctive features, i.e., that have a consistent function in the specific writing system. Examples include the dieresis in German indicating vowel fronting, and the "caron" or háček in Czech indicating palatalisation; (2) those that are used to distinguish phonemes, usually consonants, but in an inconsistent manner; this is a very flexible type of diacritic used in an inconsistent manner such as in the adoption of a "foreign" writing system and its adaptation in order to represent the phonemes of the adopting language, e.g., not only dots added to Arabic rasms to distinguish consonants in Arabic, but also those added to represent non-Arabic consonants that occur in languages such as Persian, Urdu, and Sindhi; (3) Those that indicate vowels in abjad writing systems such as Arabic and Hebrew.