diff --git a/lib/twitter_cldr.rb b/lib/twitter_cldr.rb
index 2e159b6c1..a8c8c7803 100644
--- a/lib/twitter_cldr.rb
+++ b/lib/twitter_cldr.rb
@@ -143,7 +143,7 @@ def find_fallback
 
     def lowercase_locales_map
       @lowercase_locales_map ||= supported_locales.inject({}) do |memo, locale|
-        lowercase = locale.downcase
+        lowercase = locale.to_s.downcase.to_sym
         memo[lowercase] = locale unless lowercase == locale
         memo
       end