diff --git a/database/books.go b/database/books.go
index f2c3125..77624ad 100644
--- a/database/books.go
+++ b/database/books.go
@@ -151,9 +151,7 @@ func updateBook(coll *mgo.Collection, id string, data map[string]interface{}) er
 	for k, _ := range data {
 		record.Changes[k] = book[k]
 		if k == "lang" {
-			if lang := metadataLang(data); lang != "" {
-				data["_lang"] = lang
-			}
+			data["_lang"] = metadataLang(data)
 		}
 	}
 
@@ -220,9 +218,18 @@ func buildQuery(q string) bson.M {
 }
 
 func metadataLang(book map[string]interface{}) string {
+	text_search_langs := map[string]bool{
+		"da": true, "nl": true, "en": true, "fi": true, "fr": true, "de": true,
+		"hu": true, "it": true, "nb": true, "pt": true, "ro": true, "ru": true,
+		"es": true, "sv": true, "tr": true}
+
 	lang, ok := book["lang"].([]string)
 	if !ok || len(lang) == 0 || len(lang[0]) < 2 {
-		return ""
+		return "none"
 	}
-	return strings.ToLower(lang[0][0:2])
+	lcode := strings.ToLower(lang[0][0:2])
+	if text_search_langs[lcode] {
+		return lcode
+	}
+	return "none"
 }