To achieve the goal of a multi lingual CQ5-based application, you may use CQ I18n implementation (API) to access the translated strings from the ResourceBundle, according to your language.
In the XML definition of a component, the dialog.xml, use the key directly in the text field, e.g.
fieldLabel="app.component.key"CQ5 will resolve the reference automatically.
In Java Script, CQ5 provides the method
In Java we implemented a Localization service, that loads all keys from JCR.
In JSP you can use after importing I18n