Not sure whether Ajax calender tool kit, has the option to support multiple indian language.
Any way, .NET components are going to work by default in the language defined in the page culture property in your page directive. This directive also fix the date format and all the culture relative parameters and preferences.
This is an example to set them work for English-United Kingdom
<![CDATA[<%@ Page Language="C#" Culture="en-UK" UICulture="en-UK" %>]]>