"New Developments in Formal Languages and Applications" is a scholarly book that deals with the theory of formal languages, which is considered the foundation of theoretical computer science. This discipline has its roots in mathematics and generative linguistics and finds applications in numerous research areas that involve the manipulation of symbols, such as discrete mathematics, bioinformatics, natural language processing, pattern recognition, text retrieval, machine learning, cryptography, and data compression. The book presents the essential findings from rapidly growing subfields of formal language theory and makes them accessible to a broad audience. It offers extensive bibliographic references for further study and also formulates open problems. The target audience includes students and graduates in computer science or mathematics, as well as graduates from other disciplines who possess basic mathematical knowledge. The work serves as an introduction to formal language theory and its applications and is a valuable source of information in computational theory.