Download and Install
Please note that this extension only works with Arduino 1.6.8 and higher.
Download the Indian language extensions for Arduino (a zip file). Unzip it.
You get five files: 'arduino-core.jar', 'pde.jar', 'indian_language_translation_resources.txt', 'indian_language_transliteration_resources.txt' and 'keywords.txt'.
Place all five in the lib directory under the directory where you've installed Arduino.
The new arduino-core.jar, pde.jar and keywords.txt will replace the standard arduino-core.jar, pde.jar and keywords.txt files in the lib directory.
Change the font used by the IDE to one that supports Unicode.
To do that, open the Preferences dialog from File->Preferences, and in the Preferences dialog, box click on the link to the preferences.txt file.
Edit the font name there to one that supports Unicode if required. In Windows, you can change the font name from "Monospaced" to "Arial Unicode MS".
Remember to open and change preferences.txt only after the Arduino IDE has been shut down.
Disclaimer: This is experimental code. It is still in development. It has only been tested on Windows.
We recommend that teachers only use it after becoming familiar with Arduino programming.
Known issue: Your Indian language programs must be saved before validation or compilation.