diff --git a/config/locales/diaspora/en.yml b/config/locales/diaspora/en.yml
index a454d8bb8..351df28da 100644
--- a/config/locales/diaspora/en.yml
+++ b/config/locales/diaspora/en.yml
@@ -51,7 +51,7 @@ en:
               invalid: "is invalid."
             username:
               taken: "is already taken."
-              invalid: "is invalid. We only allow letters, numbers, and underscores"
+              invalid: "is invalid. We only allow letters, numbers, and underscores."
             email:
               taken: "is already taken."
         person: