It's hard to get players to use specific speech patterns, and harder to teach them to get it right. I've worked on a game which tried to get players to use pseudo-Elizabethan prose (in a particularly ham-handed way, granted), but in practice what happened was the people who didn't care just used natural speech, and the people that did used whatever butchered old-timey dialect they thought would be appropriate for their character. Most people didn't care.