If the default language switcher bar is giving you trouble, this might help you out.

This snippet suits you if:

• You have a site with all language modules configured
• Test prefix-language switching by doing the following:
  • Go to a node that has a translation (e.g. http://www.example.com/content/my-story
  • Add the prefix of an installed language ( e.g. http://www.example.com/it/content/my-story for italian )
  • If you cannot see the translated version, you have a configuration issue or the node is not translated
• You have nodes with language-specific content (haven't tested it with language-neutral content, but don't anticipate any problems)
• You want your users to be able to switch to the same page in a different language, but the language switcher block isn't working

In my case, languages worked perfectly if you added their prefix, but the language switcher just didn't work. So I made a simple custom block to emulate its functionality.

The following have been tested on Drupal core 6.17, using modules: Locale and Content Translation from core, and Internationalization from contribs.

It's really nothing fancy, but if you have improvements or find it useful, let me know:

Add a custom block via /admin/build/block/add
Use PHP filter for the body ( you need to enable the PHP filter module if you cannot see this )
Paste in the following code:

// Switch to FALSE to get an english-only menu
$use_native = TRUE; 

//*************************************
// DON'T EDIT BELOW THIS LINE
global $language;
$languages  = language_list();
$active     = "";


// Must remove this from URL before passing to l()
$active_langs = array_keys($languages);       // Get an array of lang objects
$prefix       = "/".$language->language."/";  // Build the active lang prefix
$path         = request_uri();                // Get the current URL

if ( strpos($path, $prefix) !== FALSE ) {
  // Active path carries a language prefix, remove it
  $path = substr($path, strlen($prefix));
} else {
  // Even with no prefix, must remove starting '/' to allow Drupal
  // to recognise the path as internal
  $path = substr($path, 1); 
}

// At this point you have the clear relative path to the current page, 
//  eg "content/my-cool-story"

print '<ul class="language-switcher">';
foreach ( $languages as $lang) {
  // Add an aditional class to apply CSS to active language
  if ( $language->language == $lang->language ) { 
    $active = " active"; 
  } else {
    $active = "";
  }
  // Choose language label
  if ( $use_native ) { 
    $label = $lang->native;
  } else {
    $label = $lang->name;
  }
  
  print 
    '<li class="language-option'.$active.'">'.
      l($label, $path, array('language'=>$lang)).
    '</li>';
}
print "</ul>";

Save and you're done.

A couple of notes:

• You can change the variable $use_native to FALSE if you prefer an all-english menu, like "English Greek Italian" instead of "English Ελληνικά Italiano"
• The code adds some CSS classes to your block:
  • language-switcher to the entire ul
  • language-option to each language list item
  • active to the active language item

Enjoy :)