Yes, I checked it in incognito mode.
Here is what I did:
Blank install. I also tried the "site-languages" installation template, same problem here
Modules "Languages Support", "Languages Support - Fields", "Languages Support - Page Names" and "Languages Support - Tabs" installed (in correct order)
Added new language named "de" in "Setup" / "Languages"
Changed type of field "title" to "PageTitleLanguage"
Edited page "Home" and entered "Startseite" in new language tab
Edited PHP Template "basic-page.php" to prove that user is guest
Now I open the procject's admin area a new incognito browser session. After login, Home page looks like that:
After logout and a browser restart, I open the homepage in a incognito window again:
That's ok, because guest still having default language set. Now I change the default language of the "guest" user in the backend:
Logout, browser restart... Then I load the Home page again and it's still english (default):
To be sure that the german version works, I enter a name for the german home page in the Pw backend:
Now when I open the URL (Logout, Browser restart...) adding "/de" to the URL, the correct version is shown:
I do not know what's wrong. My collegue tested a Processwire installation in Windows by XAMPP, I use a Debian 8 Vagrant Box. We also tested older versions of Processwire, we could not get it work in any version