diff --git a/lib/configuration.js b/lib/configuration.js
index d1fb9248d801ba3ec7091a13a496888daffd575e..81cf11b78551518685adc5afc33474c7857592bc 100644
--- a/lib/configuration.js
+++ b/lib/configuration.js
@@ -136,7 +136,7 @@ var conf = module.exports = convict({
     port: 'integer{1,65535}?',
     host: 'string?'
   },
-  default_lang: 'array { string }* = [ "en-US" ]',
+  default_lang: 'string = "en-US"',
   supported_languages: 'array { string }* = [ "en-US" ]',
   locale_directory: 'string = "locale"',
   express_log_format: 'string [ "default", "dev" ] = "default"',