Hello,
this is my experience with multilanguage with one important note on Joomla 2.5 and Seblod v2.
With Seblod you can create multilanguage site and you don't need to create duplicate of content types, search, list etc... main is to use live value of language tag in Search types and to write all labels with upperacase. After that add your translation to all languages (you can analyse Seblod default xx-YY.com_cck.ini language files).
Some example: in your content type you have field for tags, that label (site) have to be written like this: TAGS. After that in language file Seblod will search translate for COM_CCK_TAGS and if it find that, it will render your translation string (pay attention on prefix: COM_CCK_).
It's important to understand that you have admin part/backend and frontend, but also content (some content type) in content position, and modules (eg. form, list...) in modules positions and depends on it your translation strings goes to different locations (admin/language or language) and different language files, eg. : xx-XX.com_cck.ini , mod_cck_search.ini , xx-XX.com_content.ini...
Additional note is if you create some dropdown list it's important not to use some special characters in list options (-,#* etc.. except space). And about space if you have in your drop-down list something like "NEW APARTMENTS" Seblod will search for COM_CCK_NEW_APARTMENTS="Your translation string".
Also you can have problems with some translations like java script popups (validation) etc., but it's simple copy/paste/rename/ file and rename string parts in it... Or some specific like xx-YY.plg_cck_field_validation_required.ini etc., but sugestion is to use Joomla system language debugger and you can easily find where is translation problem...
regards