Python is slowly becoming one of the most preferred programming languages of many big companies. It is easy to learn and has a wide audience base. Scala is also gaining momentum as the preferred choice due to its fast performance and advanced features.
Data scientists are usually recommended to learn Python and Scala for Spark, because Java does not support Read-Evaluate-Print-Loop, and R is not recommended for general purpose. Both Python and Scala are easy to learn and will help data experts get productive fast.