Hiring a Lex Yacc developer brings expertise in compiler construction and interpreter design to your team. They can efficiently translate high-level language into machine code, optimize code, and debug complex issues. Their skills in parsing and syntactical analysis can be crucial in software development, especially in creating programming languages, compilers, and interpreters. They can also help in creating software tools that require language parsing. Their knowledge can enhance the performance, reliability, and security of your software. Hence, a Lex Yacc developer can contribute significantly to your software development projects.