The Coh-Metrix™ readability checker is among the few that analyse the variations in grammar that make a text easier or harder for readers. Coh-Metrix reviews the structure of successive sentences to show how readable they would be for both first- and second-language users of English. It also analyses other factors that support readers’ comprehension of text, including the relative frequency of words (how familiar they are likely to be to adult readers), and the connectivity between words across the text.