The canonical Lisps still widely used today are Common Lisp, Scheme and Emacs Lisp. They all belong in the same family, and syntax / semantics are close. Porting code from Scheme to Common Lisp can be a lot easier than going from Python 2 to Python 3.
Clojure is something else entirely which is why a lot of people don't consider it a Lisp.
> Honest question: how do you communicate between two Lisp processes on two different machines?
If you want to use built-in object serialization, there is print and read.
> Common Lisp, Scheme and Emacs Lisp... all belong in the same family
Could you say more about what you mean by this? Is there another family of Lisps that excludes these three? I've met people who make a big deal about lisp-1 vs lisp-2 (https://en.wikipedia.org/wiki/Lisp-1_vs._Lisp-2), and which is the right way to be a Lisp, but I think maybe those people just enjoy being pedantic.
Clojure is something else entirely which is why a lot of people don't consider it a Lisp.
> Honest question: how do you communicate between two Lisp processes on two different machines?
If you want to use built-in object serialization, there is print and read.