Benefits
- Screen reader software (JAWS) needs to know what language your pages are written in, so it can pronounce your words properly when it reads them aloud. If you don't identify your language, JAWS will try to guess what language you're using, and it can guess incorrectly, especially if you quote source code or include other non−language content in your pages.
- Google benefits, even if you are writing in English, but especially if you are writing in some other language. According to the Google Zeitgeist, 50% of Google users search in languages other than English, and many of these users specify in their Google preferences to only search for pages in specific languages. Google's language auto−detection algorithms are better than most, but why make Google's job more difficult?
How to do it
look up your language code here.<html lang="en">
<blockquote lang="en">
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</blockquote>