As an update to the method of having everything related to Zend_Translate and Zend_Locale in the Bootstrap, here is an alternative using an Controller Plugin that does the grunt work of validating, selecting and updating the Zend_Locale, Zend_Registry & Zend_Session using Zend_Session_Namespace. And we are using poedit .po & .mo files as the source as usual.
A recurring problem for site developers is implementing a solid way to create and maintain multilingual sites, this article series is my feeble attempt to guide you through how to quickly implement the Zend_Translate in an Zend Framework 1.9.x site.
The procedures and best practices for this is unfortunately like training a dog, everyone has a different way of doing it and an opinion, so the methods and code I show here are take out of applications that are running in production so if you have a better way of doing it please feel free to comment!.