Ok I just looked it up on google.

there is a video on YT search for "martin garrix dancefair"

in few words, it's a female vocal: reverse it, load it in fruity slicer, automatic chops and send it to piano roll. After that just play with different slices. If you don't have FL studio i believe you can do it manually or thru FXpansion Geist.

I thought it was a plugin. So he is using fruity slicer on a vocal expansion pack ? or a female acapella from a song.