Index: t3lib/class.t3lib_befunc.php
===================================================================
--- t3lib/class.t3lib_befunc.php	(Revision 105)
+++ t3lib/class.t3lib_befunc.php	(Revision 110)
@@ -807,6 +807,59 @@
 
 		return $sysLanguages;
 	}
+	
+	/**
+	 * 
+	 * Note: doesn't respect the q=-rating by now. Should perhaps be implemented
+	 *
+	 * @param	boolean		Include lang-variants as en-us or de-de?
+	 * @return	array		All languages accepted by the user's browser, in order in which they appear in _SERVER[HTTP_ACCEPT_LANGUAGES]
+	 */
+	function getBrowserAcceptLanguages($includeSubLanguages = false) {
+		$langs_tmp = t3lib_div::getIndpEnv('HTTP_ACCEPT_LANGUAGE');
+		$tmp_arr = t3lib_div::trimExplode(',', $langs_tmp, true);
+		
+		$langs = array();
+		foreach ($tmp_arr as $langstring) {
+			if (strpos($langstring, ';') > 0) {
+				$lang = substr($langstring, 0, strpos($langstring, ';'));
+			} else {
+				$lang = $langstring;
+			}
+			
+			if (strlen($lang) > 0) {
+				if (!$includeSubLanguages && substr_count($lang, '-') > 0) {
+					$lang = substr($lang, 0, 2);
+				}
+				if (!in_array($lang, $langs)) {
+					$langs[] = $lang;
+				}
+			}
+		}
+		
+		return $langs;
+	}
+	
+	/**
+	 * Returns the available backend-languages (checks for the language-keys in typo3conf/l10n/
+	 * 
+	 * @return	array		The available languages
+	 */
+	function getAvailableBELanguages() {
+		global $LANG;
+		
+		$lang = array();
+		
+		$theLanguages = t3lib_div::trimExplode('|',TYPO3_languages);
+		foreach($theLanguages as $val)  {
+			if ($val != 'default' && !@is_dir(PATH_typo3conf.'l10n/'.$val)) {
+				continue;
+			}
+			
+			$lang[$val] = $LANG->sL('LLL:EXT:setup/mod/locallang.xml:lang_'.$val);
+		}
+		return $lang;
+	}
 
 	/**
 	 * Returns a page record (of page with $id) with an extra field "_thePath" set to the record path IF the WHERE clause, $perms_clause, selects the record. Thus is works as an access check that returns a page record if access was granted, otherwise not.
Index: t3lib/class.t3lib_div.php
===================================================================
--- t3lib/class.t3lib_div.php	(Revision 105)
+++ t3lib/class.t3lib_div.php	(Revision 110)
@@ -1474,6 +1474,21 @@
 	function uniqueArray($valueArray)	{
 		return array_unique($valueArray);
 	}
+	
+	/**
+	 * Returns the key of a value in a given array.
+	 * 
+	 * @param	array		Array containing the values
+	 * @param	string		Value to search for and if found return its key.
+	 * @return	string/int	The key of the value in the array
+	 */
+	function getArrayKeyForValue($array,$cmpValue) {
+		foreach ($array as $k=>$v) {
+			if ($v == $cmpValue) {
+				return $k;
+			}
+		}
+	}
 
 	/**
 	 * Removes the value $cmpValue from the $array if found there. Returns the modified array
Index: typo3/index.php
===================================================================
--- typo3/index.php	(Revision 105)
+++ typo3/index.php	(Revision 110)
@@ -290,35 +283,46 @@
 	 * @return	string		HTML output
 	 */
 	function makeLoginForm()	{
+		global $LANG, $LOCAL_LANG, $TYPO3_CONF_VARS;
 
+			// output the language-selector-menu
+		$lang = t3lib_BEfunc::getAvailableBELanguages();
+		asort($lang);
+		
+		$content .= '<div class="langselect" style="text-align:right;"><select name="lang" style="margin-top:10px;" onChange="document.location.href = \''.t3lib_div::getIndpEnv('SCRIPT_NAME').'?lang=\'+this.options[this.options.selectedIndex].value">'.chr(10);
+		foreach ($lang as $k=>$l) {
+			$content .= '<option value="'.$k.'"'.($LANG->lang==$k ? ' selected="selected"' : '').'>'.$l.'</option>'.chr(10);
+		}
+		$content.='</select></div>';
+
Index: typo3/template.php
===================================================================
--- typo3/template.php	(Revision 105)
+++ typo3/template.php	(Revision 110)
@@ -2112,7 +2112,14 @@
 // ******************************************************
 require_once(PATH_typo3.'sysext/lang/lang.php');
 $LANG = t3lib_div::makeInstance('language');
-$LANG->init($BE_USER->uc['lang']);
+if ($BE_USER->uid) {
+	$LANG->init($BE_USER->uc['lang']);
+} elseif (t3lib_div::_GP('lang') != '' && strpos(TYPO3_languages, t3lib_div::_GP('lang')) !== false) {
+	$LANG->init(t3lib_div::_GP('lang'));
+} else {
+	$langs = t3lib_BEfunc::getBrowserAcceptLanguages();
+	$LANG->init($langs);
+}
 
 
 
Index: typo3/sysext/lang/lang.php
===================================================================
--- typo3/sysext/lang/lang.php	(Revision 105)
+++ typo3/sysext/lang/lang.php	(Revision 110)
@@ -136,6 +136,10 @@
 	 * @return	void
 	 */
 	function init($lang,$altPath='')	{
+		
+		if (!is_array($lang)) {
+			$lang = array($lang);
+		}
 
 			// Initialize the conversion object:
 		$this->csConvObj = t3lib_div::makeInstance('t3lib_cs');
@@ -146,12 +150,21 @@
 
 			// Finding the requested language in this list based on the $lang key being inputted to this function.
 		$ls = explode('|',$this->langSplit);
-		while(list($i,$v)=each($ls))	{
-			if ($v==$lang)	{	// Language is found. Configure it:
-				$this->langSplitIndex=$i;		// The index of the language as found in the TYPO3_languages list
-				$this->lang = $lang;			// The current language key
+		foreach ($lang as $l) {
+			if ($l == 'en') {
+				$l = 'default';
+			}
+				// if this language is not available, proceed with the next
+			if ($l != 'default' && !@is_dir(PATH_typo3conf.'l10n/'.$l)) {
+				continue;
+			}
+			
+			if (in_array($l, $ls))	{	// Language is found. Configure it:
+				$this->langSplitIndex=t3lib_div::getArrayKeyForValue($ls, $l);		// The index of the language as found in the TYPO3_languages list
+				$this->lang = $l;			// The current language key
 				if ($this->helpUrlArray[$this->lang])	$this->typo3_help_url=$this->helpUrlArray[$this->lang];	// The help URL if different from the default.
 				if ($this->charSetArray[$this->lang])	$this->charSet=$this->charSetArray[$this->lang];		// The charset if different from the default.
+				break;
 			}
 		}