1. A computer-implemented method of determining a difficulty level of a text, comprising: determining with a processing system a number of cohesive devices present in a text; determining with the processing system a number of cohesive devices expected in the text; calculating with the processing system a cohesiveness metric based on the number of cohesive devices present in the text and the number of cohesive devices expected in the text; and identifying a difficulty level of the text based upon the cohesiveness metric.