Is there any way to evaluate the language a post/page is written in? I am building a multilingual site and am almost pulling my hair out trying to get the front-end navigation to take the chosen language into account. So far the polylang plugin http://wordpress.org/extend/plugins/polylang/ has worked fine for everything else.
The main language of a post should be saved in a post meta field. There is no way to detect that automatically. Even Google’s heuristics fail regularly with that.
So add a custom field
… what language the post was written in.
Here is a very simple example for a language selector. It will be visible on every post type with a Publish metabox.
… will return the post’s language if available.