As the well-known simple view of reading postulates, effective reading comprehension
requires two essential component skills: accurate recognition of words and
linguistic comprehension (Hoover & Gough, 1990). Implicit in the model, linguistic
comprehension entails broader oral language processing skills, such as vocabulary,
verbal working memory, and morphosyntactic skills. Deciphering the written code
into spoken language, understanding the meaning of written words, morphological
and syntactic processing of linguistic units, as well as their integration in working
memory, are central to reading comprehension. Accordingly, there is an extensive
body of research supporting the significant effect of word recognition and oral
language processing skills (i.e., vocabulary, verbal working memory, and morphosyntactic
skills) on reading comprehension for both L1 learners (e.g., Cain, Oakhill,
& Bryant, 2004; Ouellette, 2006) and L2 learners (e.g., Droop & Verhoeven, 2003;
Nakamoto, Lindsey, & Manis, 2008). Difficulties in either of these two component
skills can contribute to reading comprehension difficulties. For instance, weaknesses
within the oral language domain can contribute to reading comprehension
difficulties even when children have adequate word recognition skills (Nation,
Clarke, Marshall, & Durand, 2004; Swanson, Sa´ez, Gerber, & Leafstedt, 2004). In
fact, among older primary school children, oral language weaknesses seem to be the
major source of reading comprehension difficulties (Catts, Tomblin, Compton, &
Bridges, 2012).
Although word recognition and oral language skills are distinct component skills
with independent contributions to reading comprehension, they are also reciprocally
related. Vocabulary knowledge may facilitate word recognition and thereby
influence reading comprehension indirectly via word reading skills (Nagy,
Berninger, & Abbot, 2006; Tunmer & Chapman, 2012). At the same time, reading
is the primary medium through which new vocabulary is acquired. In line with this
account, significant relationships between oral language and word reading skills