Really? I feel like these two in written form are pretty different, and I don't have any real knowledge of South Asian languages.
Personally I feel Thai and Lao are harder to tell apart (I've resorted to: Lao is more curvy, Thai uses more straight lines), and also how to tell apart Czech from Slovakian, or Danish from other Nordic languages. Of course there are other ways to tell where you are, and if you only rely on written language you will not become a great player.
I'd watch GeoRainbolt[1] and all the pros that play in his tournaments.