OS X Lion: About bidirectional text
While some languages, such as English, Spanish, and Chinese, are written from left to right, others, such as Arabic, Hebrew, Yiddish, Persian, Pashto, and Urdu, are written from right to left. When right-to-left text is mixed with left-to-right text, it is called bidirectional text. Mac OS X includes support for entering and editing bidirectional text.
To use a right-to-left language, such as Arabic or Hebrew, choose the input source you want to use from the Input menu in the menu bar (looks like a flag or character). Then, to insert words from a left-to-right language, such as English, choose that input source from the Input menu. You can switch back and forth between input sources using the Input menu.
Switch from one language to another
In Mac OS X, the first character you enter in a paragraph determines the default direction for the rest of the text you enter in that paragraph. If you want to specify the direction of text, you can use the bidirectional text menu or the bidirectional keyboard shortcuts. For more information about specifying the direction of text, see: