Handling date translation is not entirely done within the <code>.po</code> files. Complete handling of date translation for each language/culture is done inside a dedicated date handler module.
The need for a separate module comes from the requirements to handle culture-specific parsing and displaying
if dates. For example, the month and day order is different between most european coutries and the US. Also, each language has its own set of acceptable modifier and qualifiers for the date: things like "from X to Y" or "between X and Y" may have differentword order. Same with "around", "calculated", "estimated". Add to this calendar names, and you have a compelling need for a dedicated module. See the [[Date Handler]] page for details on why and how to create such a module.