Converter from Facebook's locales XML to PHP array.

composer.json

{
  "name": "yoast/facebook-util",
  "require": {
    "symfony/dom-crawler": "^2.6",
    "symfony/css-selector": "^2.6"
  }
}

convert.php

<?php
require __DIR__ . '/vendor/autoload.php';

// from https://www.facebook.com/translations/FacebookLocales.xml
$xml     = file_get_contents( __DIR__ . '/FacebookLocales.xml' );
$crawler = new \Symfony\Component\DomCrawler\Crawler();
$crawler->addXmlContent( $xml );
$locales = $crawler->filter( 'locale' );
$output  = "array(\n";

foreach ($locales as $locale) {
    $locale         = new \Symfony\Component\DomCrawler\Crawler( $locale );
    $representation = $locale->filter( 'representation' )->text();
    $name           = $locale->filterXPath( '//englishName' )->text();
    $output .= "\t'{$representation}', // {$name}.\n";
}

$output .= ");";

echo $output;