What does her "Dad" whisper to her?

Rating: Null/10 (6 November 2004)

When Ellie (Jodi Foster) is on the alien world and the alien that is posing as her dead Father is telling her it's time to leave, he whispers something to her and then kisses her.
Is there any significance to what he whispers to her?
I watched that last part of the movie several times, still not seeing anything.
I'm glad they never tried to make a sequel to this, even though it got left open for one. 99% of sequels are just the pits.
As a summary, this is a great flick, definitely worth the watch, a lot of names in this movie, too.