If you are feeling adventurous, you can try the tools “Lex” and “Yacc”. These are tools traditionally used for creating a compiler for a programming language.
“Lex” is a lexical analyzer, it’s the tool that “tokenizes” the given string, and declares what is a number, what is a variable etc etc
“Yacc” stands for “yet another compiler compiler”. It is a tool that you use to define the syntax of your language, like what does declaring a variable look like? Can I assign a string to an int variable? What happens if I call a function that doesn’t exist?
If I remember currently, those tools were originally used to create early C compilers. Since then C has changed to custom-made tools.
Needless to say, making a language is vastly different than making a game. If you decide to give it ago, keep in mind there’s going to be a lot of new concepts. You can search online for more info on both tools I mentioned here. Both “Lex” and “Yacc” are free and open-source.