Index: trunk/src/org/openstreetmap/josm/tools/I18n.java
===================================================================
--- trunk/src/org/openstreetmap/josm/tools/I18n.java	(revision 13783)
+++ trunk/src/org/openstreetmap/josm/tools/I18n.java	(revision 13790)
@@ -116,4 +116,5 @@
         languages.put("it", PluralMode.MODE_NOTONE);
         languages.put("ja", PluralMode.MODE_NONE);
+        languages.put("ko", PluralMode.MODE_NONE);
         // fully supported only with Java 8 and later (needs CLDR)
         languages.put("km", PluralMode.MODE_NONE);