I have Drupal 6 with Spanish set as default language since the beginning of the project.
As I didn't know Drupal had some problems with translations, I started creating everything (node types, taxonomies, etc) in spanish. But now, I have to edit some of those things (not all of them) cause when I go to the translate interface and search for a term that is in spanish, Drupal only gives me the chance to translate it to spanish, and not to english. It's like Drupal believes that term is in English.
Well, I created a content type with the title "Información laboral" (which means Job Information). That term is well recognize by Drupal, and lets me translate it to English as Job Information. It's all ok. That content type is a "profile content".
The profile content types, add a block of information in the profile page with an autogenerated title based on the original content type title. The problem is that the term sent to translation for this autogenerated title is considered by Drupal to be in English and only lets me translate it to spanish, when the original text is already in spanish. If I place an english term, when it's asking for an spanish one, when i go to the profile page, that title is always "Información Laboral" (in english or spanish page).