diff --git a/src/Carbon/AbstractTranslator.php b/src/Carbon/AbstractTranslator.php
index 8b8fe089ee..ffe82e43ca 100644
--- a/src/Carbon/AbstractTranslator.php
+++ b/src/Carbon/AbstractTranslator.php
@@ -159,6 +159,8 @@ public function resetMessages($locale = null)
             return true;
         }
 
+        $this->assertValidLocale($locale);
+
         foreach ($this->getDirectories() as $directory) {
             $data = @include sprintf('%s/%s.php', rtrim($directory, '\\/'), $locale);