The SitePoint PHP blog has a post from editor Bruno Skvorc showing you how to integrate gettext with Twig to make it easier to internationalize your application with multiple languages and strings.

There are many approaches for adding new languages to your application’s UI. Though some userland solutions like symfony/translation are arguably simpler to use, they’re slower than the good old native gettext by an order of several magnitudes.

In this tutorial, we’ll modify an English-only application to use gettext. Through this, we’ll demonstrate that getting internationalization up and running in an already existing app is not only possible, but relatively easy.

He starts with some of the bootstrapping you'll need to do to get the "nofw" project up, Twig installed and them hooked together. He briefly introduces gettext and how it's used in PHP (with the _() handling) and provides an example defining a locale and the language files to match. He shows how to generate the .pot files, add a new language and the code needed to hook in the Twig_Extensions_Extension_I18n extension. The post ends with some "bonus scripts" to help make things a bit simpler: bash scripts to hide some of the complexity of the process.