How to prepare valid xml files from a module including translations?

[Duketown]

I've developed one module and working on another one. It is not all that hard for me to work completly in english in the module it self. For the next version of CMS I've been in contact with a great translator (thanks again Donnut). He requested me how I prepared an XML from my module and how the languages are incorporated.
The XML was just a push of the button in the extension part.
The languages brought me the following questions:
1 - If you only work in one language, is it up to the person that will use the module to get the translation using the translation center (or svn)?
2 - Is it up to the developer to check the translation center just before preparing a new version?
3 - Typing this question got me thinking: the translation is always a version behind. Is that a correct thought?
4 - Is the developer 'responsible' for the translations if he/she includes it in the downloadable version?