Piwik\Plugins\UserLanguage\Columns\Language::configureSegments PHP Method

    protected function configureSegments()
    {
        $segment = new \Piwik\Plugin\Segment();
        $segment->setCategory('Visit Location');
        $segment->setSegment('languageCode');
        $segment->setName('General_Language');
        $segment->setAcceptedValues('de, fr, en-gb, zh-cn, etc.');
        $this->addSegment($segment);
    }