As long as it’s in the same database, you can use the global $wpdb, just like esmi said. Here’s the link from wordpress:
http://codex.wordpress.org/Class_Reference/wpdb
Well, i’ve somehow managed to get around with it and solved the case.
It’s in
http://codex.wordpress.org/Category_Templates
Instead of sub-domains, I could get them all inside categories and named the categories as similar as directory structure.
So I now have:
http://www.domain.com/english/
http://www.domain.com/french/
http://www.domain.com/german/
Then I created category-x.php template for each language.
The x is the category number, which we can see from the database at table wp-terms.
It’s not sub-domain, but it works great, I now can create special template for each category. 😀
