For multilingual sites, do I set up a separate taxonomy? If I decide to set up an additional language for my site, do I need to manually set up a translated version of my existing taxonomy, or is there a module that can manage that process for me (not the translating part, obviously)?
The I18N project gives you multiple ways to deal with multi-language taxonomies:


Assign a vocabulary a language, making it specific for that language only
Translate Terms into different languages
Assign each term a language, so that you can have different terms based on the chosen language, but still a common vocabulary.