Geek talk:
From the universe of warhammer 40k
The race known as the ork comunicate in a very basic english words and noises.

Dakka dakka has multiple meanings but a general translation would be: "BANG BANG"
Its suposed to be mimicing the sound their "shootas" ( guns) make when fired.

they often say it while fiering their guns.

1)dakka dakkas are a group of people who come from there homeland and TOTALY sponge off of our government.they usualy wear leather jackets and jeans,you can usualy spot a dakka car as a honda civic with tinted windows and round about 8 other dakkas in the back seat.