Each computer user makes use of Locales, even when they don't know it. Applications lacking localization support, normally have implicit support for one particular locale (the locale of the author). When a class or function makes use of localization, we say it is locale-aware. How does the code know which localization the user is expecting?
A locale string or object identifying a supported locale gives
Zend_Locale and its subclasses access to information about the
language and region expected by the user. Correct formatting, normalization, and
conversions are made based on this information.