If I rewrote C to use BEGIN and END instead of { and }, then that's not inventing an esoteric language, but new syntax for an existing language.
In particular, a Turing Machine is a model while both Brainfuck and Groot are languages. It's easy to see how each of these languages is directly translated into a Turing Machine model (providing them a choice of semantics). Indeed, due to their isomorphism we need only translate one of them to have a faithful translation of the other "for free".
Better yet, Brainfuck and Groot both have a privileged semantic model which is more or less identically a Turing Machine (except Brainfuck merely specifies that the tape is at least 30,000 bytes long and Groot mentions site not at all while Turing Machines are explicitly infinite).
So, they're really closely related to a Turing Machine but honestly separate things more closely related to one another (via isomorphism) than to TMs directly (via semantic mapping).
If there exists, in popular culture, a character with a comically limited vocabulary (e.g. Groot, The Librarian in Discworld) then there shall be a Brainfuck variant based on its vocabulary. (In our example, Grootlang and Ook)
Now, automating that by putting enough NLP together to scan social media and news sites to classify popular characters with a comically limited vocabulary and automatically generate a Brainfuck variant based upon said character's vocabulary? That's the hard part... ;)
http://13thdimension.com/wp-content/uploads/2014/07/acstarlo...
(On the other hand, the fully-talking character was a bit of a jerk, so perhaps it's better this way.)
But, to be fair, the earlier version is based on Groot being a monster, a villain. They re-imaged a lot of the Guardians of the Galaxy to have a more proper spaced based origin.
i am Groot
On topic: I too don't think "another brainfuck interpreter" is very interesting, but I enjoyed sort-of-a-compiler for brainfuck implemented here: https://www.hashcollision.org/brainfudge/ by Danny Yoo. You can get something out of even the most useless of examples sometimes :)