The authors examine the degree to which first (L1) and second language (L2) speakers of English are able to distinguish between simplified or authentic reading texts from L2 instructional books and whether L1 and L2 speakers differ in their ability to process linguistic cues related to this distinction. These human judgments are also compared to computational judgments which are based on indices inspired by cognitive theories of reading processing. Results demonstrate that both L1 and L2 speakers of English are able to identify linguistic cues within both text types, but only L1 speakers are able to successfully distinguish between simplified and authentic texts. In addition, the performance of a computational tool was comparable to that of human performance. These findings have important implications for second language text processing and readability as well as implications for material development for second language instruction.