EDIT:
How does google Chrome’s “translate” feature know the original language of a page?
ORIGINAL QUESTION:
Please help i want to know how works the translation in Google Chrome when appear the translation menu in upside of window, how know the browser in what language it is the page
I guess Google translate compare words from page text with words from its dictionaries. For example, if a page contains many german words, it’s treated as a page in german language. Also, there are a couple of ways to specify page language in HTML code of page. Google translate will use this settings if they’re available on the page.