About bidirectional fonts
Microsoft Excel is designed to display and print both right-to-left and left-to-right text. For best results, the program should use a font that contains both right-to-left and left-to-right language characters. Some fonts available with Office and bidirectional Windows operating systems contain both right-to-left and left-to-right characters.
If you choose a font that does not contain both right-to-left and left-to-right characters, existing text in one or both languages may be displayed using a secondary font, such as Tahoma. For further information, refer to "Unicode support" in Microsoft Office Help.