Different languages have different directions of writing. In the western world most languages write Left-to-Rights (or LTR). However, a good number of languages/scripts are Right-to-left, or RTL). They include: Arabic and Hebrew.
LanguageAndScriptCode of the DDEX message should be used to determine the writing direction.
The title text in the example below should be presented from left to right (as the language is Hebrew)
<Title LanguageAndScriptCode="he"> <TitleText>אָלֶף־בֵּית עִבְרִי</TitleText> <Title>
In some cases a text contains LRT and RTL portions. In that case the
LanguageAndScriptCode shall be set to the main language used and the Unicode characters to switch direction shall be used. They are:
‬Pop Directional format
Details on how to use these can be found on http://www.i18nguy.com/markup/right-to-left.html