The speech you hear decodes the brainwave matrix.
4 seconds sound clip from The Hitchhiker's Guide to the Galaxy (1981) - Episode 1 sitcom.
You can hear this line at 00:28:49.520 in the Blu-ray version of the TV Series.
Quote context
[...]
- We're going into hyperspace!
- I'll never be cruel to a gin and tonic again!
- The Babel fish is small, yellow, leech-like, and probably the oddest thing in the universe.
- The speech you hear decodes the brainwave matrix.
- The argument runs something like this.
- I refuse to prove that I exist, says God, for proof denies faith, and without faith I am nothing.
- Oh dear, says God, I hadn't thought of that, and promptly vanishes in a puff of logic.
[...]