Vocabulary is well documented as a predictor of reading comprehension and school success (Cunningham & Stanovich, 1997; Davis, 1944 & 1968; Singer, 1965; Spearitt, 1972; Thurstone, 1946; Anderson & Nagy, 1991; Baker, Simmons, & Kame\u27enui, 1998; Becker, 1977; Cunningham & Stanovich, 1998). Through the research of the National Reading Panel (2000), vocabulary was identified as one of the five facets for improving students\u27 reading along with phonemic awareness, phonics, fluency, and comprehension. Research has estimated that for every word known by a student who is able to use morphology and context, an additional one to three words should then be understandable (Nagy & Anderson, 1984). Readers who have acquired these skills have the potential to figure out the meanings of countless unknown words in an independent fashion. Figuring out the meanings of unknown words and understanding the vocabulary is an essential skill for proficient reading (Foil & Alber, 2002). Having students look up words in a dictionary and practice their definitions is insufficient in developing a deeper understanding of words. Therefore, researching the effects of vocabulary instruction seems vital, since it is known that reading independently produces higher rates of vocabulary. Students with learning disabilities, however, do not engage in the amount of reading necessary to develop higher vocabularies by itself (Jitendra, Edwards, Sacks, & Jacobsen, 2004)
