I like the confluence of ML and array languages happening right now. I know Pandas and NumPy are their offspring, but I like the array-oriented PLs. An ELM (Extreme Learning Machine) in J [1], CNNs in APL [2], and APL-to-GPU toolchains like Futhark/apltail [3,4]. I'll have to look at shapeRank.

[1] https://github.com/peportier/jelm

[2] https://dl.acm.org/doi/10.1145/3315454.3329960

[3] https://futhark-lang.org/blog/2016-06-20-futhark-as-an-apl-c...

[4] https://github.com/melsman/apltail/