{{ pageAddAsset('javascript', zasset('@ZikulaSettingsModule:js/ZikulaSettingsModule.Block.locale_switcher.js')) }}
{% form_theme form with [
    'bootstrap_4_horizontal_layout.html.twig',
] only %}
<p>{% trans %}Select a locale:{% endtrans %}</p>
{{ form_start(form) }}
{{ form_widget(form.locale) }}
{{ form_end(form) }}