it now does, words were changed to conform to the Old Tamil phonological system, for example "Kr̥ṣṇa" → "Kaṇṇan". Most of his works are oriented on the basic Malayalam family and cultures and many of them were path-breaking in the history of Malayalam literature Writing system Aside from the Malayalam script, the Malayalam language has been written in other scripts like Latin, Syriac and Arabic. Suriyani Malayalam was used by Saint Thomas Christians (also known as Nasranis) until the 19th century. Arabic scripts particularly were taught in madrasahs in Kerala and the Lakshadweep Islands. Malayalam script Historically, several scripts were used to write Malayalam. Among these were the Vatteluttu, Kolezhuthu and Malayanma scripts. But it was the Grantha script, another Southern Brahmi variation, which gave rise to the modern Malayalam script. The modern Malayalam script bears high similarity to Tigalari script, which was used for writing Tulu language in Coastal Karnataka (Dakshina Kannada and Udupi districts) and the northernmost Kasaragod district of Kerala. It is syllabic in the sense that the sequence of graphic elements means that syllables have to be read as units, though in this system the elements representing individual vowels and consonants are for the most part readily identifiable. In the 1960s Malayalam dispensed with many special letters representing less frequent conjunct consonants and combinations of the vowel /u, u:/ with different consonants. Malayalam script consists of a total of 578 characters. The script contains 52 letters including 16 vowels and 36 consonants, which forms 576 syllabic characters, and contains two additional diacritic characters named anusvāra and visarga. The earlier style of writing has been superseded by a new style as of 1981. This new script reduces the different letters for typesetting from 900 to fewer than 90. This was mainly done to include Malayalam in the keyboards of typewriters and computers. In 1999 a group named "Rachana Akshara Vedi" produced a set of free fonts containing the entire character repertoire of more than 900 glyphs. This was announced and released along with a text editor in the same year at Thiruvananthapuram, the capital of Kerala. In 2004, the fonts were released under the GNU GPL license by Richard Stallman of the Free Software Foundation at the Cochin University of Science and Technology in Kochi, Kerala. Chillu letters A chillu (, ), or a chillaksharam (, ), is a special consonant letter that represents a pure consonant