The general guiding principle of licensing software is that you're not licensing the computer language that the application was written in, but rather, the application so created by the language.
In other words, you are licensing the behavior of the application that is represented by the code written in the language, not the language itself. Since you're talking about the language itself, licensing has nothing to do with it. In fact, you're not bound by Stata's license unless you agree to it, by using their software.
So licensing has nothing to do with it, from Stata's point of view.
The real question is, is the Stata language itself protected by copyright or patent? If you want to host a Stata interpreter that you have written yourself, using the same language specification that Stata uses, you should check with Stata to see if it runs afoul of any copyright or patent issues.