I've watched Mars Attacks plenty of times. Every time I watch it, I always hear "Ut, ut, ut!" when the Martians talk. That's also the sound I make when I imitate them.
However, I've seen all over the place people using "Ack" instead of "Ut". I've listened carefully to their dialogue, and I just don't hear "Ack" at all. I hear "Ut".
Is my hearing impaired? Or is everyone using the wrong word?
EDIT over 2 years later
I can't believe I just realized the actual pronunciation I meant to relay is more of an "Uht" just a hard start of more of an "Ahh" sound. Just the pitch of the voice starts off already relatively high.
So really more of an "AHT!" sound mixed with "UHT!".
Ut ut, ahht!