It has been frequently observed that even those who learn an L2 in the target
community for an extended period of time, such as in an immersion school or in a
natural setting where the target language is used, still produce grammatical errors of
some forms (Doughty & Williams, 1998). Having been exposed to the positive input
for a lengthy period of time, they may be fluent in the language but still show some
errors and traces of non-nativeness in their output. This observation allows us to
know that language learning does not occur automatically only by being exposed to
the language input. In addition, many research studies (e.g. White, 1991) have indicated
that positive evidence alone is not enough to allow L2 learners to discover the target
language system. Schmidt (1990) also argues that consciousness, of some form, plays
an active role in L2 learning and that L2 learning cannot take place without learners’
noticing of the input they are exposed to. Therefore, some scholars hypothesize that
L2 learners will do better if some of their attention has been drawn to language forms
in a communicative and meaningful context (Lightbown & Spada, 2006; Long & Robinson,
1998). Sharwood-Smith (1993) also agrees that learners’ consciousness should
be raised, and one way to do this is to enhance the input, making it salient enough for
the learners to notice so that they can acquire it later.
However, research results on the effects of input enhancement on form
learning are mixed and contradictory. For example, White (1998) found that typographically
enhanced input in reading passages could help French-speaking learners
of English to improve their use of possessive determiners, although there was little
difference between the experimental group and the control group, which received
no such enhanced input. Lee (2007) also found that textual enhancement facilitatedlearning of the target feature, English passive voice. Similarly, Simard (2009) examined
the effects of different kinds of enhancement and found that learners receiving
capital letter enhancement obtained the highest scores and performed significantly
better than those receiving other enhancement formats. However, Kim (2006) found
that typographical enhancement alone did not help the learners to recognize the form
and meaning of vocabulary studied. In addition, De Santis’s study (2008) indicated
that although textual enhancement helped the learners to be aware of the presence of
the target form (third person singular -s) in reading, it did not facilitate learners’ oral
production of this target feature. This is in line with Izumi’s experimental study (2002)
which investigated the effects of output-induced activity and input enhancement on
the acquisition of English relativization. He found that exposure to enhanced input
did not result in learners’ acquisition of the target feature. Izumi also called for the
reexamination of the construct of noticing. In conclusion, previous studies on input
enhancement have revealed mixed results. (For a more detailed review, see Han et al.,
2008.) Han et al. also note that “this lack of congruence in the findings is arguably a
natural consequence stimulated by the numerous methodological idiosyncracies characterizing
the individual studies” (p. 600).
The issues of whether form-focused instruction is necessary for learners to
acquire language forms and, if so, how the language forms should be presented have
been extensively debated, and research results are still mixed and controversial. For
these reasons, more studies are needed for better understanding of this issue.