Get prefer language by parsing HTTP_ACCEPT_LANGUAGE header

kotoblog_parse-http-accept-language-header.php

<?php
$prefLocales = array_reduce(
  explode(',', $_SERVER['HTTP_ACCEPT_LANGUAGE']), 
  function ($res, $el) { 
    list($l, $q) = array_merge(explode(';q=', $el), [1]); 
    $res[$l] = (float) $q; 
    return $res; 
  }, []);
arsort($prefLocales);

/*
This get you from headers like this
string 'en-US,en;q=0.8,uk;q=0.6,ru;q=0.4' (length=32)
array like this
array (size=4)
  'en-US' => float 1
  'en' => float 0.8
  'uk' => float 0.6
  'ru' => float 0.4
*/