Joomla 2.5 and later have core support for multilingual content. But there are some extra steps involved, in order to set it up properly. There are plenty of tutorials out there: http://multilingual-joomla-demo.cloudaccess.net/multi-lingual-steps-by-steps.html
Briefly the process involves the following steps:
- Enable and configure the core language plugins
- Install the additional translation packs
- Add the corresponding content languages
- Prepare your categories structure to reflect your multilingual content. - Note that you will have a root category for all languages and then a root category for each language.
- Set the main language for your homepage
- Create the corresponding Menu Structure for all your languages
- Start writing content for each language
- Configure and Publish the Language Switcher module.