Andy Hunt and Dave Thomas have long recommended learning a new language each year, especially those languages that teach new concepts.
Functional languages have made that easier. They behave in a different way than the languages many of us grew up on — procedural like C or languages derived from C. Plus, the polyglot programming movement has driven the interest in functional languages as one of the languages you might want to learn.
Programmers need to understanding the advantages of using a functional language, such as productivity, power of expressiveness, reliability, stateful objects, concurrency, natural concurrency, modularity, and composability [05:37]. Though a search still exists for a magic bullet [06:29] to make it easier for programers to better solve the problem of concurrency. CPU speeds have been stuck at roughly the same level for the last four to five years. Programmers have been given is more transistors on a chip, hence more CPUs and more cores to work with making concurrency one of the most difficult issues facing computer scientists today. Enter functional programming with improved debugging and the ability to write more reliable code in a concurrent environment.” Editorial Radar: Functional languages - O’Reilly Radar