Update README.md

Author: Lauren McCarthy

README.md

@@ -78,3 +78,6 @@ If you've contributed to this website (or any other part of the p5.js project),
 
 ## Etc
 * Introducción a p5.js - The repository for the book and PDF production of Introducción a p5.js can be found [here](https://github.com/processing/p5.js-getting-started-es).
+
+## Separately hosted language versions
+* [https://p5js.jp/](https://p5js.jp/) - 日本語 (Japanese)