Q: what country, wat do they do? wat language?
A: It is a religious holiday of India. Language is Hindi. They pray, fast and also have a lot of fun. There are lots of processions, prayers to deity, Fairs.... See this link: http://www.mysoredasara.com/ - Mysore City celebrations. More: Dasara, also called "Navaratri", is among the most important festivals celebrated in India. Unlike the festival of Dussera, the so-called "festival of joy," this is celebrated for 10 days in some parts of the subcontinent, that is India. It signifies the Victory of good over Evil. You could read this link too: http://en.wikipedia.org/wiki/Vijayadashami