Newer languages build on the concepts of the older thus students will be able to easily pick the older languages up later. I suggest Agda/Idris/Haskell in addi

Newer languages build on the concepts of the older thus students will be able to easily pick the older languages up later. I suggest Agda/Idris/Haskell in addition to C as it's rather trivial to write your own assembler in functional languages then use C to write missing parts of a full runtime system. This also allows students to explore writing their own compilers to better understand languages like C, C++, and even Java (bytecode isn't far away).