Up and running in minutes

Everything needed to install the plugin, show the switcher and extend it from your own theme.

Installation

Install from the WordPress plugin directory, or with WP-CLI.

wp plugin install multilify --activate

Use the shortcode in any post or page, or the template tag in a theme file.

[multilify_switcher]

<?php multilify_switcher(); ?>

Translate any post type, and hook into the output where you need to.

add_filter( 'multilify_post_types', function ( $types ) {
    $types[] = 'product';

    return $types;
} );

Six hooks, and that is the whole surface.

multilify_post_types: Which post types get translation panels. Add product for WooCommerce.
multilify_translated_title: The translated title, just before it is output.
multilify_translated_content: The translated content, just before it is output.
multilify_flag_choices: The flags offered in the language picker.
multilify_locale: The locale resolved for the current request.
multilify_enable_browser_detection: Whether a first-time visitor is sent to their browser's language.

Stated plainly, because finding out after installing is worse.

Page builders that render from their own stored data, such as Elementor. Multilify translates what passes through the_content, which covers the block editor and the classic editor.
Menus and widgets. Post and page content only, for now.
WooCommerce prices, attributes and variations. Product titles and descriptions translate; the rest is WooCommerce's own data.