The 22-year-old Frenchman has spent the last two seasons with Boavista and is Reading boss Steve Coppell’s first signing of the summer.
Royals director of football Nicky Hammond said of the £1m signing: “Kalifa is a 6ft 2in central midfielder who has also played in defence.
“He has real athletic ability and the technical attributes that should be well-suited to the Premiership.”
