That would be my first question too.

Hi Calvin Koepke ! Great question! There are various discussions on the web about this topic.

Here is another great article that got me going: hackernoon.com/machine-learning-with-javascript-p…

I think to start in ML you can use whatever language you like. The problems that arise in ML are mostly language agnostic and as I figured out, the difference between the languages are minimal. I simply don't want to copy python code when most of the time I am working with JS. I will reconsider my findings when I reach the limitations of JS, but for now I am far from it :)