silverstripe-framework/tests/php/i18n/i18nTest/_fakewebroot/i18ntestmodule/code/subfolder/i18nTestSubModule.php

<?php

use SilverStripe\Core\Object;

class i18nTestSubModule extends Object
{
    public function __construct()
    {
        _t('i18nTestModule.OTHERENTITY', 'Other Entity');

        parent::__construct();
    }
}