if you plan offering a web site in multiple languages, there are different alternatives, depending on the content and organization of your site:

1. Multiple web sites, one per language, with a common landing page
   Pros: No special modules required, web sites are completely independant with individual content, user base and management
   Cons: synchronization of content requires a lot of attention, otherwise site structure may diverge; If switching between language versions of a page should be provided, a custom sulution is needed
    
2. A single site with branches per language being displayed in menu
   Pros: No special modules required, easy to manage
   Cons: special menu required, site structure may diverge
    
3. A single site with page localisation and multilingual modules
   Pros: transparent localization, easy to manage
   Cons: specific multilingual modules required, currently only a small number of ML modules available. 
    
4. Language specific pages in DNN 5.5.x
   Pros: single language moduls can be used, sync between languages is handled by DNN core framework
   Cons: UI not intuitive, adding content is exhausting, a number of errors occur

Both first options are preferable, if the content varies between langaueges, e.g. there is one main langauge and other languages with parts only of the site content. In all other cases I suggest using option 3 with page localization by Effority (free), Locopon free) and Apollo Software, ML modul are also available from www.dnnwerk.de. This Web Site uses Modules by Apollo.