Translation:Họ nhảy múa.
What is the difference between "Họ nhảy múa" and "Họ nhảy" ? What purposes does "múa" serve, and is it interchangeable with "nhảy" ?
Nhay dam sounds more like ballroom dancing, and western style dancing while mua is more implying a slower type of dance and more artistic e.g. Ballet would count under mua and not nhay dam. Dam is also implying long or western type dresses hence they are not interchangeable.