When astronauts Bowman and Poole realize that HAL has made a mistake they go to a capsule to discuss their thoughts in private. They turn off comms with the ship and test that HAL doesn't follow their orders to make sure HAL can't hear them. However HAL is watching through the capsule window and is shown reading their lips.
This dialog is however as silent for HAL as for the rest of us, and I for one couldn't do any lip reading to save my life. Is this dialog a rehash of previous shown conversation or some new dialog? What are they saying? Is there a transcript?