My 4 and a half month old still hasn't laughed......?

Oh... Thats interesting. I`m dont think theres anything you can do about it. I would just blow on her tummy and play with her.I was super silly with her. My LO was laughing and making noises since 2 months. Like fully giggling at 2 months. She would laugh everyday like 10 times. Its super cute when it happens! Good luck and keep trying.