--- loncom/interface/loncommon.pm	2007/09/10 23:03:38	1.581
+++ loncom/interface/loncommon.pm	2007/09/11 20:36:30	1.582
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # a pile of common routines
 #
-# $Id: loncommon.pm,v 1.581 2007/09/10 23:03:38 albertel Exp $
+# $Id: loncommon.pm,v 1.582 2007/09/11 20:36:30 albertel Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -2563,6 +2563,29 @@ sub preferred_languages {
     return @genlanguages;
 }
 
+sub languages {
+    my ($possible_langs) = @_;
+    my @preferred_langs = &preferred_languages();
+    if (!ref($possible_langs)) {
+	if( wantarray ) {
+	    return @preferred_langs;
+	} else {
+	    return $preferred_langs[0];
+	}
+    }
+    my %possibilities = map { $_ => 1 } (@$possible_langs);
+    my @preferred_possibilities;
+    foreach my $preferred_lang (@preferred_langs) {
+	if (exists($possibilities{$preferred_lang})) {
+	    push(@preferred_possibilities, $preferred_lang);
+	}
+    }
+    if( wantarray ) {
+	return @preferred_possibilities;
+    }
+    return $preferred_possibilities[0];
+}
+
 ###############################################################
 ##               Student Answer Attempts                     ##
 ###############################################################