Make sure you have a good look at Julia, this is a relative new language (some 8 years now) that is primarily aimed at quantitative/ scientific computing. Version 1.0 was just released.
Julia is best known for its Differential equation solvers and its constrained optimization DSL/solvers and its automatic differentiation and linear algebra packages. The last two of which make it great for machine learning.
It is simple yet fast (without having to resort to external compilers like Numba in Python).
