I'm using three languages. I will leave the reader to infer which I actually work in daily.
My expert friends believe this is the best for coding interviews, and is definitely the lingua franca for data science, which is a big part of Arundo's business. I recognize that at least initially it will not be very Pythonic and won't leverage all the capabilities of Python, especially Numpy, but I plan to learn them as the solutions push me to do so. Until then, code will be very verbose, but should also mean the algorithms are quite transparent.
I used Ruby at Dev Bootcamp in 2015-16, and loved how chaining methods allowed code to be concise and super readable. See my Sudoku Solver repo for an example.
This will be my first use of .NET 6.0 and C# 10.