Common Lisp programs often use keywords liberally to avoid having to use quotes. The format function is quite different between Common Lisp and Emacs Lisp. More advanced formatting codes provide such features as paragraph filling, case conversion, and even loops and conditionals. Characters are distinct from integers in Common Lisp. Some Common Lisp data types do not exist in Emacs Lisp.
All arrays are one-dimensional.
Common Lisp features that are completely redundant with Emacs Lisp features of a different name generally have not been implemented. For example, Common Lisp writes defconstant where Emacs Lisp uses defconst . While recursion works in Emacs Lisp just like it does in Common Lisp, various details of the Emacs Lisp system and compiler make recursion much less efficient than it is in most Lisps. While this would be mainly a stylistic choice in most Common Lisps, in Emacs Lisp you should be aware that the iterative forms are much faster than recursion. Also, Lisp programmers will want to note that the current Emacs Lisp compiler does not optimize tail recursion.