diff --git a/compiler2/ttcn3/compiler.y b/compiler2/ttcn3/compiler.y
index a19e4d53aaa22d6bcc2ce579c4cef8077b795852..dcfbbc5316a64ae205ba7d84eade1137c4e60ec1 100644
--- a/compiler2/ttcn3/compiler.y
+++ b/compiler2/ttcn3/compiler.y
@@ -2087,7 +2087,17 @@ GlobalModuleId: // 5
 
 optLanguageSpec:
   /* empty */ { $$ = NULL; }
-| LanguageKeyword FreeText { $$ = $2; } // sort-of 7 LanguageSpec
+| LanguageKeyword FreeText optPackageNameList { $$ = $2; } // sort-of 7 LanguageSpec
+;
+
+optPackageNameList:
+  /* empty */
+| PackageNameList
+;
+
+PackageNameList:
+  ',' FreeText
+|  PackageNameList ',' FreeText
 ;
 
 ModuleBody: