I just did a quick test and was able to get this to work.
Create a file for transfer "thingy" ==> "foobar"to en_US.moand en_US.poin wp-content/themes/mytheme/languagesthere ...
single.php
$lang_dir = get_stylesheet_directory().'/languages';
load_theme_textdomain('mytheme', $lang_dir);
Timber::render("single.twig");
single.twig
I like {{ __('thingy', 'mytheme') }}
Output
I like foobar
, , . , WPML native translate stuff