The Contao Community Alliance translation library allows easy use of various translation string sources.
It ships with a collection of various translation string providers:
In addition it also provides a translator chain using which various translators can be stacked.
It integrates into the Contao CMS providing a translator service. To use it, just get the service from the dependency container:
<?php
/** @var ContaoCommunityAlliance\Translator\TranslatorInterface */
$translator = $GLOBALS['container']['translator'];
// Get the translation of yes from the MSC domain.
$translated = $translator->translate('yes', 'MSC');
// Sub arrays known in Contao can be accessed usng the dot as separator.
$translated = $translator->translate('title.0', 'tl_content');