Julia (programming language)
Julia supports calling C (and also e.g. Fortran or Rust) without glue code, using the keyword ccall. But it's also possible to call e.g. C++, Python, Java, MATLAB and R with help of Julia libraries for that purpose, and it's also possible to use those languages to call Julia, to reuse Julia libraries (that some of are state-of-the-art, such as SciML, made for scientific machine learning, which includes e.g. that DifferentialEquations.jl package).