Sometimes when you do a Google Search you may see a link on some of the search results that say "'Translate this page." That is a sign that the page is mostly not written in English and Google can translate it using automated translation tools for you. But, a recent thread at WebmasterWorld notes that Google may sometimes offer the translate this page link even if the site is 100% written in English!
The Webmaster reports that his site is pure English but that the IP address of his server, although truely based in America, resolves to Argentina. So when you search on a result that matches his site, the search listings will contain a link for translate this page.
Tedster, WebmasterWorld administrator, accurately replies that "shouldn't happen," that Google should pick up on "different signals" such as language, meta data, links to the site and also server location. But Google should use a multitude of those criteria to make the determination if the "translate this page" link is necessary or not.
To possible situations here: (1) Google bug and (2) The Webmaster has some non-English content or meta data or links and with the combination of the server perceived location, Google serves up the "translate this page" function.
Forum discussion at WebmasterWorld.