To some extent this is already happening in languages popular for machine learning. Libraries are written in C/C++ and the users just glue things together with very accessible API's.
Re:Go 2, here we come
by erikpukinskis on Friday November 30, 2018 @02:49PM
(#18572045)
It’s already happening. For example many people code in a subset of C++.
I don't think we'll see this happen much for existing languages, but it could be a very interesting angle for a newly-designed language (or rather pair of languages).