Lisps are a highly readable family of languages, so once you know one Lisp it's pretty easy to read the rest, and very quick to get up to speed in them so you can write your own code in pretty much any other Lisp dialect.
I went from Common Lisp to Chicken Scheme to eLisp and found the transitions very painless.
I've also peeked at code in various other Lisp dialects, and they've always been very readable to me.
If you're asking instead about DSLs written in Lisp, then the relationship of those DSLs themselves to Lisp is up to the author of the DSL in question. They can make the DSL very similar to Lisp or very different. It's entirely up to them.
Most of the Lisp code I've seen has stuck pretty close to Lisp itself, which makes it easy to read for anyone who knows Lisp.
I went from Common Lisp to Chicken Scheme to eLisp and found the transitions very painless.
I've also peeked at code in various other Lisp dialects, and they've always been very readable to me.
If you're asking instead about DSLs written in Lisp, then the relationship of those DSLs themselves to Lisp is up to the author of the DSL in question. They can make the DSL very similar to Lisp or very different. It's entirely up to them.
Most of the Lisp code I've seen has stuck pretty close to Lisp itself, which makes it easy to read for anyone who knows Lisp.