You can define your language Tag in HTML 5. W3Validator will validate your tag in website. I used it. It help you in Searching.
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<!DOCTYPE HTML><!--[if lt IE 7 ]><html class="ie ie6" lang="en"><![endif]--><!--[if IE 7 ]><html class="ie ie7" lang="en"><![endif]--><!--[if IE 8 ]><html class="ie ie8" lang="en"><![endif]--><!--[if (gte IE 9)|!(IE)]><!--><html lang="en"><!--<![endif]--><head>
