diff --git a/main/install/index.php b/main/install/index.php
index 6d6f2621fe..038eb18866 100755
--- a/main/install/index.php
+++ b/main/install/index.php
@@ -43,6 +43,10 @@ session_start();
 require '../inc/lib/main_api.lib.php';
 require api_get_path(LIBRARY_PATH).'database.lib.php';
 
+// Including specialized libraries for the installation procedure.
+require_once 'install_upgrade.lib.php'; //also defines constants
+require_once 'install_functions.inc.php';
+
 // The function api_get_setting() might be called within the installation scripts.
 // We need to provide some limited support for it through initialization of the
 // global array-type variable $_setting.
@@ -52,21 +56,27 @@ $_setting = array(
 	'permissions_for_new_files' => '0660'
 );
 
-// Loading language files.
-// TODO: It would be nice browser's intrface language to be detected at this point.
-require api_get_path(SYS_LANG_PATH).'english/trad4all.inc.php';
-require api_get_path(SYS_LANG_PATH).'english/install.inc.php';
+// Determination of the language during the installation procedure.
 if (!empty($_POST['language_list'])) {
 	$search = array('../', '\\0');
 	$install_language = str_replace($search, '', urldecode($_POST['language_list']));
-	if (!is_dir(api_get_path(SYS_LANG_PATH).$install_language)) {
-		$install_language = 'english';
-	}
-	include_once api_get_path(SYS_LANG_PATH).$install_language.'/trad4all.inc.php';
-	include_once api_get_path(SYS_LANG_PATH).$install_language.'/install.inc.php';
 	api_session_register('install_language');
 } elseif (isset($_SESSION['install_language']) && $_SESSION['install_language']) {
 	$install_language = $_SESSION['install_language'];
+} else {
+	// Trying to switch to the browser's language, it is covenient for most of the cases.
+	$install_language = detect_browser_language();
+}
+
+// Language validation.
+if (!array_key_exists($install_language, get_language_folder_list())) {
+	$install_language = 'english';
+}
+
+// Loading language files.
+require api_get_path(SYS_LANG_PATH).'english/trad4all.inc.php';
+require api_get_path(SYS_LANG_PATH).'english/install.inc.php';
+if ($install_language != 'english') {
 	include_once api_get_path(SYS_LANG_PATH).$install_language.'/trad4all.inc.php';
 	include_once api_get_path(SYS_LANG_PATH).$install_language.'/install.inc.php';
 }
@@ -86,10 +96,6 @@ api_set_internationalization_default_encoding($charset);
 // Page encoding initialization.
 header('Content-Type: text/html; charset='. api_get_system_encoding());
 
-// Specialized libraries for the installation procedure.
-require_once 'install_upgrade.lib.php'; //also defines constants
-require_once 'install_functions.inc.php';
-
 // Some constants
 define('SYSTEM_INSTALLATION', 1);
 define('MAX_COURSE_TRANSFER', 100);
@@ -232,9 +238,9 @@ if (!isset($_GET['running'])) {
 	$adminPhoneForm	= '(000) 001 02 03';
 	$institutionForm    = 'My Organisation';
 	$institutionUrlForm = 'http://www.chamilo.org';
-	$languageForm	    = 'english';
 	// TODO: A better choice to be tested:
-	//$languageForm	    = api_get_interface_language();
+	//$languageForm	    = 'english';
+	$languageForm	    = api_get_interface_language();
 
 	$checkEmailByHashSent	= 0;
 	$ShowEmailnotcheckedToStudent = 1;
@@ -355,7 +361,7 @@ if ($encryptPassForm == '1') {
 				document.getElementById('optional_param5').style.display = '';
 				document.getElementById('optional_param6').style.display = '';
 				init_visibility = 1;
-				document.getElementById('optionalparameters').innerHTML='<img style="vertical-align:middle;" src="../img/div_hide.gif" alt="" /> <?php echo get_lang('OptionalParameters'); ?>';
+				document.getElementById('optionalparameters').innerHTML='<img style="vertical-align:middle;" src="../img/div_hide.gif" alt="" /> <?php echo get_lang('OptionalParameters', ''); ?>';
 			} else {
 				document.getElementById('optional_param1').style.display = 'none';
 				document.getElementById('optional_param2').style.display = 'none';
@@ -365,7 +371,7 @@ if ($encryptPassForm == '1') {
 				document.getElementById('optional_param4').style.display = 'none';
 				document.getElementById('optional_param5').style.display = 'none';
 				document.getElementById('optional_param6').style.display = 'none';
-				document.getElementById('optionalparameters').innerHTML='<img style="vertical-align:middle;" src="../img/div_show.gif" alt="" /> <?php echo get_lang('OptionalParameters'); ?>';
+				document.getElementById('optionalparameters').innerHTML='<img style="vertical-align:middle;" src="../img/div_show.gif" alt="" /> <?php echo get_lang('OptionalParameters', ''); ?>';
 				init_visibility = 0;
 			}
 		}
diff --git a/main/install/install_upgrade.lib.php b/main/install/install_upgrade.lib.php
index 397e696192..f8a69f6a56 100755
--- a/main/install/install_upgrade.lib.php
+++ b/main/install/install_upgrade.lib.php
@@ -392,25 +392,114 @@ function get_sql_file_contents($file, $section, $print_errors = true) {
 }
 
 /**
- *	Returns a list of language directories.
+ * Tries to detect browser's language.
+ * @return string		Returns a language identificator, i.e. 'english', 'spanish', ...
  */
-function get_language_folder_list() {
-	$result = array();
-	$exceptions = array('.', '..', 'CVS', '.svn');
-	$search       = array('_latin',   '_unicode',   '_corporate',   '_org'  , '_KM',   '_');
-	$replace_with = array(' (Latin)', ' (unicode)', ' (corporate)', ' (org)', ' (KM)', ' ');
-	$dirname = api_get_path(SYS_LANG_PATH);
-	$handle = opendir($dirname);
-	while ($entries = readdir($handle)) {
-		if (in_array($entries, $exceptions)) {
-			continue;
+function detect_browser_language() {
+	static $language_index = array(
+		'ar' => 'arabic',
+		'ast' => 'asturian',
+		'bg' => 'bulgarian',
+		'bs' => 'bosnian',
+		'ca' => 'catalan',
+		'zh' => 'simpl_chinese',
+		'zh-tw' => 'trad_chinese',
+		'cs' => 'czech',
+		'da' => 'danish',
+		'prs' => 'dari',
+		'de' => 'german',
+		'el' => 'greek',
+		'en' => 'english',
+		'es' => 'spanish',
+		'eo' => 'esperanto',
+		'eu' => 'euskera',
+		'fa' => 'persian',
+		'fr' => 'french',
+		'fur' => 'friulian',
+		'gl' => 'galician',
+		'ka' => 'georgian',
+		'hr' => 'croatian',
+		'he' => 'hebrew',
+		'id' => 'indonesian',
+		'it' => 'italian',
+		'ko' => 'korean',
+		'lv' => 'latvian',
+		'lt' => 'lithuanian',
+		'mk' => 'macedonian',
+		'hu' => 'hungarian',
+		'ms' => 'malay',
+		'nl' => 'dutch',
+		'ja' => 'japanese',
+		'no' => 'norwegian',
+		'oc' => 'occitan',
+		'ps' => 'pashto',
+		'pl' => 'polish',
+		'pt' => 'portuguese',
+		'pt-br' => 'brazilian',
+		'ro' => 'romanian',
+		'qu' => 'quechua_cusco',
+		'ru' => 'russian',
+		'sk' => 'slovak',
+		'sl' => 'slovenian',
+		'sr' => 'serbian',
+		'fi' => 'finnish',
+		'sv' => 'swedish',
+		'th' => 'thai',
+		'tr' => 'turkce',
+		'uk' => 'ukrainian',
+		'vi' => 'vietnamese',
+		'sw' => 'swahili',
+		'yo' => 'yoruba'
+	);
+
+	$system_available_languages = & get_language_folder_list();
+
+	$accept_languages = strtolower(str_replace('_', '-', $_SERVER['HTTP_ACCEPT_LANGUAGE']));
+
+	foreach ($language_index as $code => $language) {
+		if (strpos($accept_languages, $code) === 0) {
+			if (!empty($system_available_languages[$language])) {
+				return $language;
+			}
 		}
-		if (is_dir($dirname.$entries)) {
-			$result[$entries] = ucwords(str_replace($search, $replace_with, $entries));
+	}
+
+	$user_agent = strtolower(str_replace('_', '-', $_SERVER['HTTP_USER_AGENT']));
+
+	foreach ($language_index as $code => $language) {
+		if (preg_match("/[[( ]{$code}[;,_-)]/", $user_agent)) {
+			if (!empty($system_available_languages[$language])) {
+				return $language;
+			}
 		}
 	}
-	closedir($handle);
-	asort($result);
+
+	return 'english';
+}
+
+/**
+ *	Returns a list of language directories.
+ */
+function & get_language_folder_list() {
+	static $result;
+	if (!is_array($result)) {
+		$result = array();
+		$exceptions = array('.', '..', 'CVS', '.svn');
+		$search       = array('_latin',   '_unicode',   '_corporate',   '_org'  , '_KM',   '_');
+		$replace_with = array(' (Latin)', ' (unicode)', ' (corporate)', ' (org)', ' (KM)', ' ');
+		$dirname = api_get_path(SYS_LANG_PATH);
+		$handle = opendir($dirname);
+		while ($entries = readdir($handle)) {
+			if (in_array($entries, $exceptions)) {
+				continue;
+			}
+			if (is_dir($dirname.$entries)) {
+				$result[$entries] = ucwords(str_replace($search, $replace_with, $entries));
+			}
+		}
+		closedir($handle);
+		asort($result);
+	}
 	return $result;
 }