All the South Asian scripts owe their origins to the old Brahmi script which, like Latin, Greek, Hebrew, Arabic, etc. and most other alphabets is supposed to have come originally from proto-sinaitic inscriptions of which were discovered in 1904 in the Sinai peninsula. According to that theory, most alphabets have the same origin. "Many scholars link the origin of Brahmi to Semitic script models, particularly Aramaic. The explanation of how this might have happened, the particular Semitic script and the chronology have been the subject of much debate. "
The north Indian scripts are fairly similar to one another, but the scripts in which the southern Indian, Sri Lankan, Burmese and south east Asian languages are written differ quite a bit, so I wanted to compare them. Omniglot.com is a fantastic resource for this. I was surprised how easy it is to differentiate between the different scripts. Each has particular characteristics.
Kannada, spoken in Karnataka
Telugu, spoken in Andhra Pradesh
Khmer, used in Cambodia
Malayalam, used in Kerala
Tamil, used in Tamil Nadu
Sinhala script, used in Sri Lanka