(address of your school)
dated: 24th of September 2014
Subject: Invitation for a speech "future of English in India"
I'm the principal of (school) and I hereby invite you to a very important (declamation/ ceremony) that is being conducted by our school at 8th October 2014 (time). I request you to give a speech on "future of English in India". By this speech we basically want to convey our message to(the students or whatever..) that even our country can obtain high scopes in English language. We are very proud to have the presence of such an esteemed scholar like you. I hope and have a high expectation that people learn from your speech.
(your pricipal's name)