I think something important is to ensure the adults around your DS don't patronize him by infantalizing their speech when interacting with him. It's important for him to feel respected, and use of accurate terminology is a way of conveying respect for your son's interests. Other adults may slip into saccharine over-simplifications. You can run interference or, if your LO is an outspoken firecracker like mine, he will self-advocate forcefully (and mercilessly).
I remember one library visit when DS was around 18 months old and one librarian was bragging about DS to another within his earshot. He had been talking about paleobatrachuses (+1 in the Dinosaur Train votes!), which she relayed as, "He's talking about a crustacean frog. It's amazing!" To that DS replied, "No, a Cretaceous frog. Frogs are amphibians, not crustaceans."
