Harsh and Abrasive, 80% Verse and 20% Prose
Coriolanus has a reputation for harsh and abrasive language, especially when it comes to Coriolanus' style. Check out the first thing he says:
What's the matter, you dissentious rogues,
That, rubbing the poor itch of your opinion,
Make yourself scabs? (1.1.174-176)
Nope. No soft and cuddly feel good poetry here, folks. After all, the dude is super aggressive and angry, so it's fitting that his speech style is just as rough and forceful as his character. What's more, the world of Coriolanus is violent and harsh. When the play opens, the Citizens are rioting and screaming for blood. Plus, two wars go down, and the whole thing ends with our hero's violent death.
In other words, the play's language matches its tone and content exactly.
The other thing to know about Coriolanus' style is that about 80% of the play is written in verse (a.k.a. poetry) and about 20% is prose (how most regular folks talk every day). In general, Shakespeare's upper class characters (like this play's patricians) tend to speak verse, the idea being that formal verse reflects their noble and aristocratic status. (By the way, Shakespeare's favorite verse to use is iambic pentameter and you can read all about it here.)
The lower class characters (in this case, the plebeians or, Citizens) tend to speak in regular old prose. Actually, they tend to shout in regular old prose.