The ezLocalizer gets all messages (UI elements, messages, etc) from the assembly files, allows the users to localize them and then builds them back into an assembly. This assembly has to replace the original assemblies that contain English messages. These messages will be displayed regardless the SharePoint culture.
The other method to localize QWP is to use a custom list that would contain the English messages, the culture and the message to be displayed when the SharePoint culture is the same as the culture specified in the list. Please check this link for more details https://commons.quest.com/message/29778#29778. This approach accommodates the current SharePoint culture and it changes dynamically. Please note that not all QWP messages can be localized using this approach.
Please note that the ezLocalizer is a new feature and will be available in the next version of QWP.