Drawing upon sociocultural theory of Vygotsky, the current study
aims to investigate the effect of dyadic interaction in mixed and
matched level proficiency pairings on comprehension and production
of request and apology speech acts. The participants were 125 EFL
learners who were randomly assigned to control and experimental
(interaction) groups. Based on their scores in the pretest including a
pragmatic listening test and an Oral Discourse Completion Test
(ODCT), those in the experimental groups were assigned to the mixed
(H-L) and matched level (H-H and L-L) dyads. Both the control and
experimental groups received metapragmatic instruction on speech
acts; however, the experimental groups were engaged in collaborative
problem-solving tasks on speech acts for nine sessions. Following the
treatment, the posttest was administered, the results of which revealed
the outperformance of the interaction groups compared with the
control group. Moreover, mixed level dyads were found to outperform
their matched level counterparts in both measures of comprehension
and production of speech acts. The findings have pedagogical
implications for L2 teachers and practitioners on how to best pair
learners in collaborative activities.