Yep. Similar to how we used to write the high performance code in ASM and the business logic in C. Now we write the high performance code in C (or equiv. low-level language) and the high performance code in a slow but expressive dynamic language. My favorite is writing high-level code in some kind of Lisp (previously Clojure, lately Racket) because REPL-driven development makes it incredibly fast to iterate and experiment and then cement/polish it into production code all while having the same state in memory.