My eight month old niece already knows how to stand on her own and can walk when being guided. Her parents does not prefer to let her use a walker. Is there a safe alternative on teaching a toddler to walk?

Push walker or moon walkers may be of help, if you don't want to get the traditional walkers. If you really want to teach her without any baby gears at all, then just train her to walk everyday. She'll get the hang of it and eventually learn to walk on her own.