Generally the idea is that players choose their language on login, and since this is saved locally in the browser it should be a non-issue after the first time.
There is a way to change the language settings later, you have to change the URL. Normally you play at
But you can also go to
which gives you the English version of the game. Further language codes (replacing the "en" above) are
tc: Chinese (simplified, I think, not sure).