Python would be the most popular option, but, for an OO language, Ruby feels clean and intuitive to me in a way that other languages, especially Python, don't. It has a performance cost, though. The languages' performance may be roughly equivalent, but Python has more native-code libraries for a lot of things. You don't see many ML projects in Ruby. :) There's crystal-lang, but that has a much smaller community behind it.

Julia, though, if you're looking for a language that isn't OO in addition to functional.