While Windows Phone 7 is available in different languages there are still many languages it does not support. With Abjad Keyboard you can have Arabic and Hebrew Keyboard on your Windows Phone 7 Mango device.
The Abjad Keyboard is created by XDA-Forums member Dr.Dev. The developer himself mentions :
Here’s an App I have created for WP7 Mango. It gives you the ability to write in Arabic, English and Hebrew.
This is a standalone app which means you’ll need to switch to it every time you need to write in Arabic. However, thanks to Mango’s fast switching capability which made the whole thing a lot easier.
The Abjad Keyboard is a standalone application which means that it cannot entirely replace the native keyboard but you will have to activate it. However the keyboard works efficiently proving smooth typing in both languages.