The document discusses the top 5 hardest programming languages to learn in 2023: C++, Prolog, LISP, Haskell, and Malbolge. C++ is considered one of the most powerful but also hardest languages to learn. Prolog is used for artificial intelligence and logic programming. LISP is one of the oldest languages and used for high-level systems and AI. Haskell is a fully functional language based on lambda calculus. Malbolge is considered one of the most difficult languages due to its poor readability and unpredictable behavior. The document provides brief overviews of each language.