Yes! Cosmopolitan and APE are now permissively licensed under ISC terms. So they'd be a perfect fit for language authors. One of the biggest obstacles language authors encounter, is overcoming the obstacles posed by portability between operating system apis. Cosmopolitan takes care of that. You can just use the normal textbook unix apis and have it work on Windows/Linux/BSDs. Best of all, Cosmpolitan is tiny, embeddable, and unobtrusive. As in, these "fat binaries" are actually more like 16kb in size. So any language author who chooses to use it is going to have more time to focus on their vision, while reaching a broader audience from day one, with a sexy lightweight form.