Will you key in the content in Kannada and Hindi? Or do you want to get even more geeky and call in a translate script that translates into Kannada and Hindi?
If former, simple, add two custom fields and Key in using an appropriate keyboard (Not too sure if ERPNext does a good job saving and reproducing Kannada and Hindi scripts, though) key in the Names in Name Kannada and Name Hindi. This is in the customer master.
Call in these fields too when you make an invoice. Use Print formats and call in these fields into the Print Format and voila, you are good to go!
If you want to do the more geeky stuff, see how you can integrate the Google Translate APIs and calling a custom script, you should be able to translate the contents of one field into another.
How come two of you are looking for the same feature? Is there a regulatory need that both of you are trying to comply with? Just curious!