I would look at modifying some of the TabPy samples we showed at TC16. the TabPy project is on our Github at GitHub - tableau/TabPy The TC16 session is available here Sign Up | Tableau Conference Live the session is Introducing TabPy - http://tclive.tableau.com/Library/Video?vCode=BRK53875
Looking at the MonkeyLearn site I see they have a Python API available (GitHub - monkeylearn/monkeylearn-python: Official Python client for the MonkeyLearn API. Build and consume machine learn… ) so after TabPy install you will do a pip install monkeylearn and call your scripts. You can also see Bora Beran 's blog post - Leverage the power of Python in Tableau with TabPy | Tableau Software. Bora and Nathan Mannheimer presented the TC16 Session.You will then just need to figure out how to return the results back to Tableau.
MonkeyLearn looks interesting.