Thoughts: Depends what you mean by a functional language! 😊 Many of the most popular multi-paradigm languages have adopted a lot of functional ideas: functions as values, higher-order functions in the core SDK, easy ways to make immutable data structures, APIs or libraries that support lazy eval.

My impression is the stricter FP languages that try to force more of this stuff to be used at most/all times, eg Haskell, Clojure, are known to many people and are sometimes used in industry, but fairly rarely.