I think the best programming language for finance is Python. Python is an incredibly versatile and widely used programming language that has many applications in finance. It's the main language used by Quantopian, which is a platform for building trading algorithms.
Also, it's the most popular language among data scientists, who are often required to use Python to work with large datasets due to its ability to handle large sets of data efficiently. Finally, Python also happens to be one of the most common languages used in machine learning applications like natural language processing (NLP).
That being said, I'm not sure any single language is "best" for finance because there are so many different types of problems you can solve with different languages—and some problems might require several languages working together.