Diwali is basically the Hindu equivalent to Christmas.. It's supposed to celebrate God's victory over Evil or light over dark.. It's really the celebration of light so they light dias (like a candle) and do alot of fireworks. They also do something call the pudja where they buy a piece of gold and bless it sort of a way to symbolize their gods... It's about 5 days long and it's their biggest holiday.
And the dirka dirka reference is to Muslims who speak Arabic. Hindus are a completely different race, religion, and culture.