.................. Why is there so little dialogue?

KUBRICK: It's not a message I ever intended to convey in words.
2001 is a nonverbal experience; out of two hours and 19 minutes of film, there are only a little less than 40 minutes of dialogue.
I tried to create a visual experience, one that bypasses verbalized pigeonholing and directly penetrates the subconscious with an emotional and philosophic content.
To convolute McLuhan, in 2001 the message is the medium.
I intended the film to be an intensely subjective experience that reaches the viewer at an inner level of consciousness, just as music does; to explain a Beethoven symphony would be to emasculate it by erecting an artificial barrier between conception and appreciation.
You're free to speculate as you wish about the philosophical and allegorical meaning of the film, and such speculation is one indication that it has succeeded in gripping the audience at a deep level........

................    Dave: Open the pod bay doors, please, HAL. Open the pod bay doors, please, HAL. Hello, HAL, do you read me? Hello, HAL, do you read me? Do you read me, HAL? Do you read me, HAL? Hello, HAL, do you read me? Hello, HAL, do you read me? Do you read me, HAL?
    HAL: Affirmative, Dave. I read you.
    Dave: Open the pod bay doors, HAL.
    HAL: I'm sorry, Dave. I'm afraid I can't do that.
    Dave: What's the problem?
    HAL: I think you know what the problem is just as well as I do.
    Dave: What are you talking about, HAL?
    HAL: This mission is too important for me to allow you to jeopardize it...........