Thunderbird extension for Arabic
By Rayed
Thunderbird is a great email client, it has very good support for international languages, and it displays Arabic emails without any problems, the only problem that I face with it is when writing Arabic emails, unfortunately Thunderbird doesn’t have shortcut or button to change the writing direction from left-to-right used by most western languages, to right-to-left used for Arabic.
But through the power of extensions you can install this small extension (37K) that will add 2 new buttons in Compose window, one for changing the direction from LTR->RTL, and vice versa.
https://addons.mozilla.org/thunderbird/310/