{# -*- coding: utf-8 -*- This file is part of Invenio. Copyright (C) 2015-2018 CERN. Invenio is free software; you can redistribute it and/or modify it under the terms of the MIT License; see LICENSE file for more details. #}

{{_('Hello world')}}

Using ln query parameter (overrides everything else):

Using language selector macros:

{% from "invenio_i18n/macros/language_selector.html" import language_selector, language_selector_form, language_selector_dropdown %} 
language_selector
{{ language_selector() }} 
language_selector_form
{{ language_selector_form() }} 
language_selector_dropdown
{{ language_selector_dropdown() }}

Debug:

Selected language:
{{ current_i18n.locale.language }}
1. Language from request query string (?ln=):
{{ 'ln' in request.args }}
2. Language from session (key '{{config.I18N_SESSION_KEY}}'):
{{ session.get(config.I18N_SESSION_KEY) }}
3. Language from current_user:
{{ getattr(current_user, config.I18N_USER_LANG_ATTR, None) if current_user else None }}
4. Language from Accept-Language header:
{{request.headers.get('Accept-Language')}}
5. Language from default locale:
{{ config.BABEL_DEFAULT_LOCALE }}