Grammarly is an app that uses a series of powerful algortihms to study (and is actually a very useful tool for double-checking a writer's grammar, punctutaion and spelling). It decided to take a comparative look at how the respective Trump and Clinton campaigns scored in those key grammatical areas. It's also developed a method for assessing the use of "political correctness".
The results are interesting. The short conclusion, as the authors put it, is that "conservatives and liberals are more alike than you might think". Inspite of that conclusion, Trump supporters are 135% more likely to use vulgar and foul language than are the Clinton supporters, and they rely upon "politically incorrect" terms 88% more often. Finally, Trump supporters on Facebook were almost twice as likely to make grammatical errors. (It's worth noting, though, that Reddit users in both camps seem to be much more grammatically correct than are the Facebook users.)
In any case, the following inforgraphic summarizes the findings nicely and is worth a minute or two of your time.