Effects of Graded Texts on EFL College Students' Incidental ...

Besides the above potential limitations, we suspect the following additional
constraints after closer scrutiny <strong>of</strong> text sequence in TextLadder. First, from the
quantitative results <strong>of</strong> Ghardirian’s study, learners may have to learn 2 to 25 new
words for each new text depending on the length <strong>of</strong> the text. The percentages <strong>of</strong> new
words are particularly high in the first 10 to 20 texts, ranging from 8% to 16%. In
other words, if a text is about 300 words long, a learner has to learn about 25 new
words after reading them in such a short text for the first time. Nation (2001)
pointed out that “extensive reading should contain no more than 5% unknown running
words “ (p. 150). Compared to Nation’s position, the new word percentages in the
first few texts in TextLadder are still higher.
Second, though TextLadder tried to ensure that target words in word list could
appear in reading for at least five times within about 300 reading texts, there is no
control on when or how <strong>of</strong>ten learners will encounter those new words again. This
therefore leads to another problem, the low frequency <strong>of</strong> appearance for target words
will degrade incidental vocabulary learning. It may be in the tenth or twentieth text
that learners finally once again encounter the target words read in the first text.
Whether words could be acquired with such interval is questionable. Moreover, the
amount <strong>of</strong> exposure necessary for word acquisition has remained a controversial issue
with some researchers suggesting a much higher exposure amount than five times
(Horst, Cobb, & Meara, 1998; Herman, Anderson, Pearson, & Nagy, 1987).
Therefore, the five-time word acquisition threshold determined by Textladder awaits
further research verification.
Lastly, as was admitted by Ghadirian (2002), Textladder was not tested out on
real learners, hence, the actual effect <strong>of</strong> sequenced text on vocabulary learning is left
to explore.
In sum, Ghadirian’s (2002) sequencing program, TextLadder, had successfully
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