Hi
"No support from Gavick team" ? I'm here to help You in this matter
As mentioned above we currently have 3 methods of multilanguage:
1. Falang
Personaly my first class choice. You need to create a content once and than just need to translate (extra fields can be supported as well), but sure a case when diferent authors are responsible for different language versions can be problematic, but You can always select a link to a different article while translating. Honestly I never found problem I could not figure out somehow with this component.
2. Main menu based on all languages.
With this You work as with a normal joomla, but part of menu options is available for one language, are some for otheres. Switching between languages make one oprion of language visible at the time. Also a good solution, but problem is with home page which has to be different for each language. A workaround is to create a separate menu with a homepage element for one of this languages.
3. Template styles
A little problematic, but sure it's doable as well. To use it You need to create a separate menu for each language. That create a copy of a stule for each language and attache one menu per style. Problem is again a homepage which joomla doesn't always know which one to display, but it doesn;t happen often. Also a drawback is that this solution deals with a multiple styles, so sometimes change needs to be done for each style saparetaly in order to takes effect.
If You select one of this methods I'll tell more details or a step by step instruction, but I think this 2 sentences about each method should be enought to figure out the idea.