Making a Language with JavaScript.

Programming language implementations vary wildly, but the steps are roughly as follows:

• Parse source code text into abstract syntax tree (AST) such as JSON
• (Optional) Static analysis of AST to report warnings and errors
• Depending on whether you want a compiler or an interpreter:
  • Compile to executable, bytecode, JS, etc. OR
  • Evaluate the AST to run the program

Relevant: What programming language should you learn first? ʇdıɹɔsɐʌɐɾ :ɹǝʍsuɐ