My almost 7.5 month old recently has come to think that it is hilarious to screech at us - when he is happy, bored, mad, excited, etc. Did you find for your child that this was a stage? When did they stop? Anything to do to encourage a new habit?
DD is 6 months and had started screeching, and so I started fake laughing at her in a very exaggerated way, and now she does that instead... but I'm not counting on it lasting, honestly. It was too easy. lol.
He still does it, at almost 11 months. He does other stuff too-general yelling, hollering "AH DAH DAH DAH DAAAAAAH!" or "MIIIHHHHMMM", and babbling for the hell of it. But plenty of screeching.