Can someone explain what this is to someone like me that doesn't know python very well, but programs a lot in c#?

Language server protocol is the interface of a software piece that sits between an IDE and a language toolchain so you don't need to change code in the IDE to add support of new languages (you add support on the LSP server). Then server provides things such as completions/intelli-sense, navigation to definitions and some correction checking. From the anouncement TSP extends LSP for better python type awarness.