diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
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+Thank you for contributing Mstdn.app!
+=====================================
+
+## Language
+
+You can use either English or Japanese for issues or pull requests. Please feel free to make ones.
+
+issue 及び pull request は日本語で書いていただいて大丈夫です．
+
+## Templates
+
+Please use issue templates which are automatically inserted.
+
diff --git a/ISSUE_TEMPLATE.md b/ISSUE_TEMPLATE.md
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+<!-- Please do not forget to write your OS and version of Mstdn.app -->
+
+