I hear good things about Plankalkül these days. Its a bit old, but it has excellent support for electric vacuum tubes.

More serious answer: if you can't answer that question its a long road ahead. Essentially there are only 8-10 languages which cover 99% of the market. and for ultra high performance there are 4-5 choices: C, C++, Erlang, Skala, golang + maybe Java, C#.