Explicit instruction in grammar: A comparison of input-based and output-based instruction in second language acquisition

This study investigates the relative effects of two types of instruction on the acquisition of clitic direct object pronouns and past tense verb morphology by adult classroom learners of Spanish. Two types of instruction were compared: one was traditional instruction, consisting of grammar explanation and oral practice which was output based and was directed at altering the ways in which the L2 learners produce the second language; the other, called processing instruction, was input based and was directed at altering the ways in which the L2 learners process L2 input. Processing instruction aimed at altering two well documented strategies used by language learners when processing input. One consists of the so-called "S-V-O = agent-action-object strategy", according to which learners in the early and intermediate stages of language acquisition tend to interpret NVN sequences as agent-action-object or SVO sequences when processing input. The other strategy consists of the precedence given by second language learners to lexical items --temporal adverbs--over morphological markers when interpreting tense.A total of 161 subjects participated in the both the investigation on direct object pronouns and past tense verb morphology. All subjects consisted of second year learners of Spanish at the University of Illinois at Urbana-Champaign. Subjects did not participate in both studies. For each investigation, subjects were assigned to one of three instructional treatments: traditional instruction, processing instruction and no instruction, this last one being the control group. A pretest/post-test procedure (with immediate as well as delayed post-tests) was used as the means of assessing the impact of instruction. All tests consisted of both interpretation/comprehension tasks and written production tasks.The results of both investigations indicated that processing instruction seems to have a greater effect on the developing system of language learners of Spanish than traditional instruction. Processing instruction appears to have altered the way in which the subjects processed input which in turn had an effect on what they could access for production. Traditional instruction, on the other hand, had an impact on what the subjects could access for production but had little impact on how the subjects processed input.The results obtained from the present investigation have both theoretical and pedagogical implications. On the theoretical side, the present study not only makes a contribution to on-going discussion about the role of formal instruction on SLA, but it also provides support for the important role that input processing plays in SLA. On the pedagogical side, the results of the present study suggests that instead of discussing whether formal instruction "per se" makes a difference in SLA, it would be more appropriate to consider what type of formal instruction would be most effective in SLA.U of I OnlyETDs are only available to UIUC Users without author permissio