Simple language selector

<?php
$lang = '';
if(!empty($_SERVER['PATH_INFO']) && strlen($_SERVER['PATH_INFO']) >= 3){
	$path_info_lang = substr($_SERVER['PATH_INFO'], 1);
	if(preg_match('`^([a-z-]+)$`i', $path_info_lang) && is_file($path_info_lang.'.html')){
		$lang = $path_info_lang;
	}
}
if(empty($lang) && !empty($_SERVER['HTTP_ACCEPT_LANGUAGE'])){
	preg_match_all("/([[:alpha:]]{1,8})(-([[:alpha:]|-]{1,8}))?"."(\s*;\s*q\s*=\s*(1\.0{0,3}|0\.\d{0,3}))?\s*(,|$)/i", $_SERVER['HTTP_ACCEPT_LANGUAGE'], $accepted_languages, PREG_SET_ORDER);

	foreach($accepted_languages as $l){
		if(is_file(strtolower($l[1]).'.html')){
			$lang = strtolower($l[1]);
			break;
		}
	}
}
if(empty($lang)){
	header('HTTP/1.0 404 Not Found');
	$lang = 'fr';
}
include $lang.'.html';
exit;

I've got a less complicated one 😃

function autoDetectLanguage() {
  $languages = split( ",", strtolower( str_replace( "-" , "_", $_SERVER["HTTP_ACCEPT_LANGUAGE"] ) ) );

  // Cherche toutes les langues du navigateur
  // La première occurrence plausible fait foi..
  foreach( $languages as $key => $language ) {
    if ( strpos( $language, ";" ) ) {
      $language = substr( $language, 0, strpos( $language, ";" ) );
    }

    switch ( substr( $language, 0, 2 ) ) {
      case 'fr' : // fr
        return 'fr';
      case 'en' : // en
        return 'en';
     // etc.
      default:
        return 'fr';
    }
  }


}