I've been a ventriloquist for years.
4 seconds sound clip from the Mister Ed movie soundboard.
You can hear this line at 00:19:30 in the DVD version of the movie.
Quote context
[...]
- But-But the horse. I heard it... talking?
- That wasn't the horse. I'm a ventriloquist.
- A ventriloquist? That is remarkable. You didn't even move a muscle.
- Would you believe it if I were to tell you the horse actually talks?
- I've been a ventriloquist for years.
- Let me see you do that just once more while I'm watching you closely.
- I can talk while I drink a glass of water.
- Boy, there is more to you than I thought. I am amazed!
[...]