Agree with the others...when they discover they can do something, they do it all the time. She probably does like the noise, and your reaction to it..lol.
I have seen or should I say heard this in a friends baby the screeches wre so high pitched they made one jump we always thought she enjoyed hearing her own voice as she giggled afterwards, it did moderate as she got older.
No, nothing's hurting her. In fact, she seems to kind of enjoy it. Thanks.
I guess I should also say that you must be sure something isn't hurting her!
Yep. They make all kinds of noises . . . just because they can!