Building Readability Lexicons with Unannotated Corpora

Lexicons of word difficulty are useful for various educational applications, including readability classification and text simplification. In this work, we explore automatic creation of these lexicons using methods which go beyond simple term frequency, but without relying on age-graded texts. In particular, we derive information for each word type from the readability of the web documents they appear in and the words they co-occur with, linearly combining these various features. We show the efficacy of this approach by comparing our lexicon with an existing coarse-grained, low-coverage resource and a new crowdsourced annotation.