One of the symptoms of my son's autism is delayed echolalia - the repetition of words and phrases he heard hours, days or even weeks before. For a long time he has used these echoes in place of real language (though now he's starting to show some improvement). He seems to know the meaning of these phrases and uses them at appropriate times - it just sounds odd:

He says - it means
Ahoy there! - Hello
Hooray! - Yes
Ouch! - No
Are you ok? - I'm hurt
interesting - interesting

He likes to jump on his bed and can jump for 45 minutes straight. while he jumps he always has something interesting to repeat over and over:

You've got to sing!
If you dream
I know it!
G - giraffe!
T - tiger
N-Y-C (as in New York City)

If you go right now and jump on your bed repeating one these phrases, I think you'll find he's on to something.