Index: /trunk/src/org/openstreetmap/josm/gui/preferences/display/LanguagePreference.java
===================================================================
--- /trunk/src/org/openstreetmap/josm/gui/preferences/display/LanguagePreference.java	(revision 14928)
+++ /trunk/src/org/openstreetmap/josm/gui/preferences/display/LanguagePreference.java	(revision 14929)
@@ -7,4 +7,5 @@
 import java.util.ArrayList;
 import java.util.Arrays;
+import java.util.Comparator;
 import java.util.List;
 import java.util.Locale;
@@ -84,5 +85,7 @@
         LanguageComboBoxModel() {
             data.add(0, null);
-            data.addAll(Arrays.asList(I18n.getAvailableTranslations()));
+            List<Locale> locales = Arrays.asList(I18n.getAvailableTranslations());
+            locales.sort(Comparator.comparing(Locale::getDisplayLanguage));
+            data.addAll(locales);
         }