diff --git a/locales/en-US.yml b/locales/en-US.yml
index 56744a679..5842e87f9 100644
--- a/locales/en-US.yml
+++ b/locales/en-US.yml
@@ -84,10 +84,10 @@ common:
   my-token-regenerated: "Your token has been regenerated, so you will be signed out."
   i-like-sushi: "I prefer sushi rather than pudding"
   show-reversi-board-labels: "Show row and column labels in Reversi"
-  use-contrast-reversi-stones: "Make the stone color clear"
+  use-contrast-reversi-stones: "Make the stone color clear in reversi"
   verified-user: "Verified account"
   disable-animated-mfm: "Disable animated texts in a post"
-  do-not-use-in-production: 'これは開発ビルドです。本番環境で使用しないでください。'
+  do-not-use-in-production: 'This build is for development. DO NOT USE THIS IN PRODUCTION SERVER.'
   reversi:
     drawn: "Draw"
     my-turn: "Your turn"