In addition to addressing essential curriculum, today's content-area teachers are encouraged to emphasize literacy skills that are tailored to their respective disciplines (Houseal, Gillis, Helmsing, & Hutchison, 2016) as a means of developing students' abilities to read, write, and speak as disciplinary apprentices (Shanahan & Shanahan, 2012). Word learning is a fundamental component of this new emphasis. Word learning is critical as adolescents are expected to "grow their vocabularies through a mix of conversations, direct instruction, and reading" and "determine word meanings, appreciate the nuances of words, and steadily expand their repertoire of words and phrases" (National Governors Association Center & Council of Chief State School Officers, 2010, "Regular Practice With Complex Texts" section, para. 2). A promising word learning approach that can be tailored to any content area is morphological instruction