Rhetorical difference between liberals and conservatives

Rereading my last post, I had this thought.

I wonder if there has been any studies done on differences in rhetoric use by political parties that compares the parties' rhetoric against each other. Essentially, I wonder if there is any variation in the parties' rhetoric attributable to the parties' positioning on an ideological scale. It seems to me that the Democrats, and probably left of center parties in general, say "we" a lot. Republicans on the other hand say "you" a lot. Now, one could assume that over time, as parties were able to test the efficacy of certain rhetoric, there would be convergence of rhetoric such that there wouldn't be a distinguishable difference. Nonetheless, the topic intrigues me.