wpml_admin_make_post_duplicates

// this will create duplicates for the "Hello World!" post
do_action( 'wpml_admin_make_post_duplicates', 1 );

add_action( 'wp_insert_post', 'my_duplicate_on_publish' );
function my_duplicate_on_publish( $post_id ) {
	global $post;

	// don't save for autosave
	if (is_null($post))
		{
       		 return $post_id;
		}

	if ( defined( 'DOING_AUTOSAVE' ) && DOING_AUTOSAVE ) {
		return $post_id;
	}

	// dont save for revisions
	if ( isset( $post->post_type ) && $post->post_type == 'revision' ) {
		return $post_id;
	}

	// we need this to avoid recursion see add_action at the end
	remove_action( 'wp_insert_post', 'my_duplicate_on_publish' );

	// make duplicates if the post being saved:
	// #1. is not a duplicate of another or
	// #2. does not already have translations

	$is_translated = apply_filters( 'wpml_element_has_translations', '', $post_id, $post->post_type );

	if ( !$is_translated ) {
		do_action( 'wpml_admin_make_post_duplicates', $post_id );
	}

	// must hook again - see remove_action further up
	add_action( 'wp_insert_post', 'my_duplicate_on_publish' );
}