J.S.
My son is 2 and still likes to let out an occassional scream for no reason, especially if other kids are around, it becomes like a contest, and then they laugh uncontrollably. Trust me on this one, you will learn to tune it out! They are just expressing themselves, and the only thing it really hurts is our ears! When we are out in public and he does it I just use the SHhhhh! signal and he quiets down. At your babies age though people will just have to get over it!
p.s. he doesn't know that it is "nonsense", he just thinks its fun!