WordPress – How to add new multilingual post (WPML) with ACF?

You can also give a try by adding the given code to the functions.php file of the theme.

Here we are using acf/save_post hook for inserting posts.

<?php
function custom_acfform_save_post( $post_id ) {
    // Check if this is the ACF form submission
    // here field_32146789bca is the field id.
    if ( isset( $_POST['acf']['field_32146789bca'] ) ) {
        
        $post_data = get_post( $post_id );
        
        // Here we are creating a new post array for the Primary post.
        $new_post = array(
            'post_title'  => $post_data->post_title,
            'post_content'=> $post_data->post_content,
            'post_status' => 'publish',
            'post_type'   => 'post'
        );

        // Here we are inserting the new post in German Language.
        $new_post_id = wp_insert_post( $new_post );

        if ( ! is_wp_error( $new_post_id ) ) {
            // Here we are setting up the post language to German using WPML.
            do_action('wpml_set_element_language_details', array(
                'element_id'    => $new_post_id,
                'element_type'  => 'post_post',
                'trid'          => apply_filters('wpml_element_trid', null, $post_id, 'post_post'),
                'language_code' => 'de',
                'source_language_code' => 'en'
            ));

            // Link the two posts together
            global $sitepress;
            $sitepress->set_element_translations(
                array(
                'post_post' => array(
                    'en' => $post_id,
                    'de' => $new_post_id
                    )
                )
            );
        }
    }
}
add_action('acf/save_post', 'custom_acfform_save_post', 20);