Explain how multilang works

I am confused about how persiting multilang docs in the CMF actually works..

In the MenuBundle documentation I wanted to link to the CoreBundle multilang docuemntation, and explain how to persist docs there, but then it made sense to link to the PHPCR-ODM docs which use `bindTranslation`.

But then the `TranslatableInterface` has `setLocale`, so do we need to call `bindTranslation` ? Is `locale` read only? Will calling `setLocale` do anything?

Anyway, we should make all this clear here.