A simple PHP library to translate texts using Google Translate. There is also a free version of Google Translate (no API key required).
composer require nggit/php-google-translate:dev-master
require __DIR__ . '/vendor/autoload.php';
use Nggit\Google\Translate;
$translate = new Translate(array('key' => 'your_api_key', 'lang' => array('de' => 'en'))); // translate from german to english
$translate->setText('Der schnelle Braune Fuchs springt über den faulen Hund');
echo $translate->process()->getResults();
Enjoy!