I think I can understand it because I already know html/css/js/php/mysql web languages and know python/c# and for learning blockchain mining I used python for test.
Oh dear. Web languages, Python and C# won't help you at all when trying to write highly optimized low-level code.
Anyhow, could you reply what your actual goal is in the first place? Is it just a coding exercise? If so, the answer is: 'The best language is the one you're comfortable with and that is fun to write'.
If you want to develop something that competes with existing software, maybe just fork what already exists and optimize it further.
If you want to use it for Bitcoin mining, don't even bother with programming languages and go for FPGA or ASIC design, which is a whole different beast; you'd be looking at learning and understanding chip design, then implement it in VHDL or Verilog, as tromp suggested.