That's always happening to me: a stray fingernail catches a key and 'whoops' ... it's all in Chinese, or Hungarian or some other language.
Scroll down to the page, and, in the far bottom left corner, you'll see a grey box with a white word on it. Click on the drop down arrow, and you'll get a list of languages. English should be the first on the list, so just click on that and the language should revert to English. Good luck!