What Language Is This?

What language is this? Or, more properly, what script is that, as obviously it is written in a particular script.

Interesting. A man took a trip to Thailand. He went out to a restaurant one night, and when he got back to his hotel, this slip of paper was somehow in his wallet. Although he spoke a number of languages and considered himself to be something of a linguistic expert, he could not figure out what the language was or especially what the script was.

To give you a possible hint, it does resemble a number of the scripts used to write South Indian Dravidian languages and also languages in Southeast Asia. Hence, as you might have guessed if you are smart, of course it is an abugida. But now you need to figure out what an abugida is!