<?php
$reply_user_id = bbp_get_reply_author_id();
global $wp_roles;
$reply_user = new WP_User( $reply_user_id );
$roles = $reply_user->roles;
$role = array_shift($roles);
printf( isset($wp_roles->role_names[$role]) ? translate_user_role($wp_roles->role_names[$role] ) : false);
?>