How do you speak to your baby?

Hi, FTM to 4 week old tiny person here! I've recently realised I have no idea how to communicate with him. Baby talk seems ridiculous, but also telling him how my day is going seems too...adult? I often find when he is crying that I just try to shush him, instead of speaking to him. This morning he was staring at me during a feed, and I just rambled on about how the heart pumps blood to the rest of the body 🤣 Does anyone have any tips on how to speak to babies?