> I'd throw Python out too, as it's just far too slow*, which would set wrong expectations for learners. While itmcaan be sped up by writing everything in C and calling it from Python you've already thrown C out, so that's not an option.

I'm not sure I follow you. Are you saying using e.g. numpy is not okay because it's implemented in C? How does that make any sense? The cpython interpreter itself is implemented in C so everything interpreted by cpython is just as much "in C" as something else like e.g. numpy.