keep on adding grammatical rules until they can use them automatically. Rather, consistent and repeated practice changes the knowledge representation by making the stored knowledge become more specific or more analyzed through a process called restructur- ing (McLaughlin, 1990). According to Lightbown and Spada (2013), “restructuring may account for what appear to be bursts of progress, when learners suddenly seem to ‘put it all together,’ even though they have not had any new instruction or appar- ently relevant exposure to the language” (p. 110). Further, it could explain backsliding, when learners overgeneralize new rules into contexts to which they do not apply, such as applying the English -ed past tense ending to an irregular verb, as in the case of “*I eated.”
Restructuring, mistakenly appearing to be error-ridden performance or forgetting, often results in U-shaped patterns of learning, which illustrate three stages of language use, as depicted in Figure 1.3. In Stage 1, the learner produces a form that is error-free, perhaps as a result of attention on that form in classroom practice. In Stage 2, the learner produces the form but with errors, which may arise for a variety of reasons: the learner is tired, the communicative situation is too demanding, or the new learning leads to restruc- turing of existing linguistic knowledge through overgeneralization of a language concept, as in the example of “*I eated” previously cited. In the face of these circumstances, the learner “makes the very error that he or she had so recently appeared to have learned to overcome” (Segalowitz, 2003, p. 397). Finally, in Stage 3, the learner once again uses the correct form as in Stage 1, having presumably restructured his or her understanding of the original structure and perhaps of new material.
The utterances depicted in Figure 1.3 come from Lightbown’s (1983) study of French learners studying English. Lightbown hypothesizes that initially students were only presented with the present progressive form and so they used it correctly; later when pre- sented with the simple present form, they had to readjust their knowledge of the present progressive, which led to the error in reverting to the simple present in Stage 2. Further
FiGuRe 1.3 U-Shaped Behavior
Source: Republished with permission of Routledge, from S. M. Gass, Second Language Acquisition: An Introductory Course, 4th ed., 2013, p. 263; permission conveyed through Copyright Clearance Center, Inc.