Another very successful way to go about building a language is Imba.
Build a successful product with new lang https://scrimba.com, make sure the product's very hard to Jeff and take VC money.
Now you can work on the language as you please, and they can't Jeff you since nobody else can build something similar (not in a reasonable amount of time anyway)
P.S: taking VC money is optional. Scrimba is profitable so it wasn't necessary.