Klaatu Barada Nikto is the phrase Michael Rennie as Klaatu makes Patricia Neal memorize in case anything happens to him in "The Day The Earth Stood Still" 1951. The story is, if Klaatu is killed his giant robot Gort has instructions to destroy the people who have harmed him, unless he gets other instructions. That phrase is the other instructions, because after she says it to him, Gort aborts the attack, retrieves Klaatu's body and brings him back to life.
So the first word would be Klaatu says...Barada nikto cancels the attack, and orders Gort to find his master.