Python and R

Python has managed to dominate the (still) niche of Machine Learning and some domains of Artificial Intelligence. Supported by a complete ecosystem of tools, libraries as well as online courses and books, Python can not be avoided while working with these technologies.

As a heavily evolved language it might no longer be the syntactically cleanest of all, but it still remains very usefull and allows for rapidly prototyping hypothesis which is very usefull when working on large statistical analysis or automation on large datasets.

R is not related to Python, however both languages are dominant in the machine learning space and contain a lot of power when it comes to statistical analysis and big data analysis.