diff --git a/agents/toplevel/HtmlAgent.inc b/agents/toplevel/HtmlAgent.inc
index 4af26dbc..34abd31d 100644
--- a/agents/toplevel/HtmlAgent.inc
+++ b/agents/toplevel/HtmlAgent.inc
@@ -53,33 +53,104 @@
 			// Add Seminary sidebar
 			$this->addSubAgent('Seminarybar');
 		}
-		
-		
-		
-		
-		/**
-		 * Set requested language.
-		 * 
-		 * @param	\nre\core\Request	$request	Current request
-		 */
-		private function setLanguage(\nre\core\Request $request)
-		{
-			// Set domain
-			$domain = \nre\configs\AppConfig::$app['genericname'];
-			
-			// Get language
-			$locale = $request->getGetParam('lang', 'language');
-			if(is_null($locale)) {
-				return;
-			}
-			
-			// Load translation
-			putenv("LC_ALL=$locale");
-			setlocale(LC_ALL, $locale);
-			bindtextdomain($domain, ROOT.DS.\nre\configs\AppConfig::$dirs['locale']);
-			textdomain($domain);
-		}
-		
-	}
+
+
+
+
+        /**
+         * Set requested language.
+         * 
+         * @param   \nre\core\Request   $request    Current request
+         */
+        private function setLanguage(\nre\core\Request $request)
+        {
+            // Set domain
+            $domain = \nre\configs\AppConfig::$app['genericname'];
+
+            // Get language
+            $locale = $this->determineLanguage($request);
+
+            // Set Locale and Load translation
+            if(!is_null($locale))
+            {
+                //$locale = sprintf('%s_%s.UTF-8', $locale, strtoupper($locale));
+                putenv("LC_ALL=$locale");
+                setlocale(LC_ALL, $locale);
+                \Locale::setDefault($locale);
+
+                bindtextdomain($domain, ROOT.DS.\nre\configs\AppConfig::$dirs['locale']);
+                textdomain($domain);
+            }
+        }
+
+
+        /**
+         * Determine which language is either requested directly or by browser
+         * setting.
+         * 
+         * @param   \nre\core\Request   $request    Current request
+         * @return  string                          Requested language or default one
+         */
+        private function determineLanguage(\nre\core\Request $request)
+        {
+            // Get supported languages
+            $supportedLanguages = \nre\configs\AppConfig::$app['languages'];
+            if(empty($supportedLanguages)) {
+                return null;
+            }
+
+            // Get requested language
+            $language = $request->getGetParam('lang', 'language');
+            if(!is_null($language) && array_key_exists($language, $supportedLanguages)) {
+                return $language;
+            }
+
+            // Negotiate language
+            return $this->negotiateLanguage($supportedLanguages, $request->getBrowserLanguages());
+        }
+
+
+        /**
+         * Negotiate which language the browser wants most out of the supported
+         * languages.
+         * 
+         * @param   array   $supportedLanguages List of supported languages
+         * @param   array   $browserLanguages   List of browser languages
+         * @return  string                      Negotiated language or default one
+         */
+        private function negotiateLanguage($supportedLanguages, $browserLanguages)
+        {
+            if(!is_null($browserLanguages))
+            {
+                // Create array with languages and their ratings
+                $parsedLanguages = array();
+                $languages = explode(',', $browserLanguages);
+                foreach($languages as &$language)
+                {
+                    if(($pos = strpos($language, ';q=')) !== false) {
+                        $parsedLanguages[substr($language, 1, min(2, $pos-1))] = floatval(substr($language, $pos+3));
+                    }
+                    else {
+                        $parsedLanguages[$language] = 1.0;
+                    }
+                }
+
+                // Sort languages by their ratings
+                arsort($parsedLanguages);
+
+                // Get highest supported language
+                foreach($parsedLanguages as $language => $rating) {
+                    if(array_key_exists($language, $supportedLanguages)) {
+                        return $supportedLanguages[$language];
+                    }
+                }
+            }
+
+
+            // Return default language
+            return $supportedLanguages[array_keys($supportedLanguages)[0]];
+        }
+
+    }
 
 ?>
diff --git a/app/Controller.inc b/app/Controller.inc
index cdd7e7d4..3603db23 100644
--- a/app/Controller.inc
+++ b/app/Controller.inc
@@ -83,19 +83,22 @@
 			
 			// Create date and time and number formatter
 			$this->set('dateFormatter', new \IntlDateFormatter(
-				\nre\core\Config::getDefault('locale'),
+				//\nre\core\Config::getDefault('locale'),
+                \Locale::getDefault(),
 				\IntlDateFormatter::MEDIUM,
 				\IntlDateFormatter::NONE,
 				NULL
 			));
 			$this->set('timeFormatter', new \IntlDateFormatter(
-				\nre\core\Config::getDefault('locale'),
+				//\nre\core\Config::getDefault('locale'),
+                \Locale::getDefault(),
 				\IntlDateFormatter::NONE,
 				\IntlDateFormatter::SHORT,
 				NULL
 			));
 			$this->set('numberFormatter', new \NumberFormatter(
-				\nre\core\Config::getDefault('locale'),
+				//\nre\core\Config::getDefault('locale'),
+                \Locale::getDefault(),
 				\NumberFormatter::DEFAULT_STYLE
 			));
 		}
diff --git a/configs/AppConfig.inc b/configs/AppConfig.inc
index d895b5c7..9c992234 100644
--- a/configs/AppConfig.inc
+++ b/configs/AppConfig.inc
@@ -36,7 +36,10 @@
             'timeZone'          => 'Europe/Berlin',
             'mailsender'        => '',
             'mailcontact'       => '',
-            'registration_host' => ''
+            'registration_host' => '',
+            'languages'         => array(
+                'de'    => 'de_DE.utf8'
+            )
 		);
 		
 		
@@ -53,9 +56,7 @@
 			'toplevel-htmlmail'	=>	'htmlmail',
 			'intermediate'		=>	'introduction',
 			'intermediate-error'	=>	'error',
-			'intermediate-mail'	=>	'mail',
-			'language'		=>	'de_DE.utf8',
-			'locale'		=>	'de-DE'
+			'intermediate-mail'	=>	'mail'
 		);
 		
 		
diff --git a/requests/WebRequest.inc b/requests/WebRequest.inc
index 2e0f19b9..a02dba93 100644
--- a/requests/WebRequest.inc
+++ b/requests/WebRequest.inc
@@ -184,6 +184,22 @@
 		{
 			return $_SERVER['REQUEST_METHOD'];
 		}
+
+
+        /**
+         * Get languages from browser setting.
+         * 
+         * @return  string  Browser setting for accepted languages.
+         */
+        public function getBrowserLanguages()
+        {
+            if(array_key_exists('HTTP_ACCEPT_LANGUAGE', $_SERVER)) {
+                return $_SERVER['HTTP_ACCEPT_LANGUAGE'];
+            }
+
+
+            return null;
+        }
 		
 		
 		/**