diff --git a/src/org/omegat/core/segmentation/MapRule.java b/src/org/omegat/core/segmentation/MapRule.java
index 63053d32b1..1688b2472c 100644
--- a/src/org/omegat/core/segmentation/MapRule.java
+++ b/src/org/omegat/core/segmentation/MapRule.java
@@ -113,7 +113,7 @@ public void setLanguage(String code) {
                 if (code != null && code.contains("Textdateien")) {
                     languageCode = LanguageCodes.F_TEXT_CODE;
                 } else {
-                    LOGGER.atDebug().setMessageRB("CORE_SRX_RULES_UNKNOWN_LANGUAGE_CODE").addArgument(code)
+                    LOGGER.atDebug().setMessage("Unknown language code '{}' specified").addArgument(code)
                             .log();
                     languageCode = code;
                 }