Many programmers learn one platform, one language and stay in their monoculture. Learning many different programming languages can definitely change your programming style and the way you think about problems. It was certainly beneficial for me, here is why.
After learning Pascal, C in the first semester at the University I started be commercial programming career as a PHP developer (part time in the second semester). It was easy to start with and in demand so finding a part time job was easy. I never liked the language, it was not “pure”, I especially hated the function naming and parameters orders inconsistencies.
At the university I learned OOP principles and C++ and thought OOP was the answer to everything so I immediately changed my PHP programming style to incorporate it. My code became more readable and organized. Later at the university I had to learn nonprocedural Prolog and functional Haskell. I found it very difficult because I had to think in another way and came out of my comfort zone. When I finished the course I really liked Haskell and functional programming because of its clarity, readability and the fact that I could write a very compact code. But I had no practical use for it. It did not change my Programming style but made me look for a more pure and “nicer” language to learn.