As far as I know, none of these 3 work specifically in NLP, most of their work is in image processing and to the best of my knowledge none of them have any background in linguistics.
Their pricing page says that it costs them around 1$ to serve 80 searches. I really wonder how they arrive at that number. That seems shockingly expensive somehow.
> This seems like such a distant yet specific relationship type
I don't know much about it (never stepped foot outside EU/NA) but apparently some Asian countries have a pretty intricate system of kinship terms. For example Diagram IV in [1] shows different (Mandarin?) Chinese terms for what we would just call a "cousin" in English.
I also found the video by NativLang [2] on the topic pretty interesting.
scikit-learn (next to numpy) is the one library I use in every single project at work. Every time I consider switching away from python I am faced with the fact that I'd lose access to this workhorse of a library.
Of course it's not all sunshine and rainbows - I had my fair share of rummaging through its internals - but its API design is a de-facto standard for a reason.
My only recurring gripe is that the serialization story (basically just pickling everything) is not optimal.