Malayalam, the official language of kerala, is one of the south dravidian language. It is believed that malayalam is derived from tamil (kodumthamizh), another south dravidian language, during the sangam period. But many words in malayalam are borrowed from Sanskrit, and this gives rise to a counter argument about the origin of the language.
The origin of Malayalam as a distinct language may be traced to the last quarter of 9th Century A.D. Malayalam first appeared in writing in the vazhappalli inscription which dates from about 830 AD. In the early thirteenth century the Malayalam script began to develop from a script known as vattezhuthu (round writing), a descendant of the Brahmi script. But malayalam as we know now is greatly simplified from 900 glyphs, which it originally had.
From the Department of public relations, govt. of kerala:
Malayalam is classified as a South Dravidian language. It is the official language of Kerala. About 31.8 million people consider Malayalam as their mother tongue. Possessing an independent written scipt, it also has a rich modern literature. There are at least five main regionaldialects of Malayalam and a number of communal dialects. It belongs to the Dravidian family. Many words have been borrowed from Sanskrits. There are 37 consonants and 16 vowels in the script. Malayalam has a written traditional dating back from the late 9th century and the earliest work dates from 13th century. The script used is called Kolezhethu (Rod-script) which is derived from ancient Grandha Script. Malayalam differs from other Dravidian language as the absence of personal endings on verbs. It has a one to one correspondence with the Indo Aryan Devanagari syllabarry.