Exotel now supports SMS in all Indian regional languages. For example, you can send this as an SMS - रेजिस्टर करने के लिए धन्यवाद !!
It's very simple to set this up from your account.
1. Select one of the approved templates on your dashboard. You can access your approved SMS template from Here. There are many sites like http://indiatyping.com/ (with sub-domains for most Indian languages) that will allow you to type out the message in English and convert it into the regional language's script.
2. Copy that text and paste it in the SMS dialog box from the approved templates
3. If you're running an SMS campaign, paste the text in the SMS campaign dialog box.
Follow the rest of the process as usual.