diff --git a/ResourceLoaderULSModule.php b/ResourceLoaderULSModule.php
index dda84928..784db4f5 100644
--- a/ResourceLoaderULSModule.php
+++ b/ResourceLoaderULSModule.php
@@ -33,9 +33,15 @@ class ResourceLoaderULSModule extends ResourceLoaderModule {
 	 */
 	protected function getData() {
 		$vars = array();
-		$vars['wgULSLanguages'] = Language::fetchLanguageNames(
-			$this->language->getCode(), 'mwfile'
-		);
+		if ( method_exists( 'Language', 'fetchLanguageNames' ) ) {
+			// since 1.20
+			$vars['wgULSLanguages'] = Language::fetchLanguageNames(
+				$this->language->getCode(), 'mwfile'
+			);
+		} else {
+			$vars['wgULSLanguages'] = Language::getLanguageNames( false );
+		}
+
 		return $vars;
 	}
 
diff --git a/UniversalLanguageSelector.hooks.php b/UniversalLanguageSelector.hooks.php
index 4d26264e..1aa0adcf 100644
--- a/UniversalLanguageSelector.hooks.php
+++ b/UniversalLanguageSelector.hooks.php
@@ -105,7 +105,11 @@ class UniversalLanguageSelectorHooks {
 
 	protected static function isSupportedLanguage( $language ) {
 		wfProfileIn( __METHOD__ );
-		$supported = Language::fetchLanguageNames( null, 'mwfile' );
+		if ( method_exists( 'Language', 'fetchLanguageNames' ) ) {
+			$supported = Language::fetchLanguageNames( null, 'mwfile' ); // since 1.20
+		} else {
+			$supported = Language::getLanguageNames( false );
+		}
 		wfProfileOut( __METHOD__ );
 
 		return isset( $supported[$language] );
@@ -117,7 +121,11 @@ class UniversalLanguageSelectorHooks {
 	 */
 	protected static function getDefaultLanguage( array $preferred ) {
 		wfProfileIn( __METHOD__ );
-		$supported = Language::fetchLanguageNames( null, 'mwfile' );
+		if ( method_exists( 'Language', 'fetchLanguageNames' ) ) {
+			$supported = Language::fetchLanguageNames( null, 'mwfile' ); // since 1.20
+		} else {
+			$supported = Language::getLanguageNames( false );
+		}
 		// look for a language that is acceptable to the client
 		// and known to the wiki.
 		foreach ( $preferred as $code => $weight ) {
diff --git a/data/LanguageNameIndexer.php b/data/LanguageNameIndexer.php
index b8df9c53..8c2820ed 100644
--- a/data/LanguageNameIndexer.php
+++ b/data/LanguageNameIndexer.php
@@ -33,7 +33,12 @@ class LanguageNameIndexer extends Maintenance {
 	}
 
 	public function execute() {
-		$languages = Language::fetchLanguageNames( null, 'all' );
+		if ( method_exists( 'Language', 'fetchLanguageNames' ) ) {
+			$languages = Language::fetchLanguageNames( null, 'all' ); // since 1.20
+		} else {
+			$languages = Language::getLanguageNames( false );
+		}
+
 		$all = array();
 		$buckets = array();
 		foreach ( $languages as $code => $name ) {