Anna,
Language translation programs often give stupid results (try the Babelfish program in Altavista for a laugh).
So I suspect the options are:
* a set of pages for each language. This means you have to implement any changes to the dialogue design as many times as you have languages.
* if your server has any programming and file / database look-up facilities, you could have a database or a set of files containing pieces of text identified by a combination of a language code and a code (the same for all languages) whihc identifies the subject / content of the text. Then when the user choses a language, you generate each page using the selected language code plus the code for the subject / content which is needed at this point in the dialogue.
You also have to be cautious about how much conent you put into each page and each "box" in each page, because different languages require different numbers of characters to express the same idea. For example in most of the notices I've seen which are in both English and French, the French version is significantly longer.