@Imperial - in what we don't we handle Arabic Text strings, all strings are fully unicode and assuming you have the correct glyphs in the font and the text is written correctly (remembering that the characters in the string will be printed from left to right) then it will be displayed correctly.
If what you are asking when will the draw_text etc work by writing each character from right to left, then I will question whether that is what is really wanted, I have no experience with right to left languages or the expectation of anyone using right to left languages as to what they would / should expect.
Russell
NOTE: mixed up right and left