abstract while task-based instruction is considered as the most effective way to learn a language in the related literature, it is oversimplified on various grounds. different variables may affect how students are engaged with not only the language but also with the task itself. the present study was conducted to investigate language and task related engagement on the basis of the task typology and metatalk. to this end, 80 homogeneous participants in terms of the language proficiency were assigned to four groups. the groups were different in terms of opportunities they are provided with by being engaged in different types of the tasks namely jigsaw, dictogloss, text reconstruction and translation as operationally defined on the basis of ellis’definition of a task (2003). participants language related engagement was measured by evaluating syntactic devices, intonational, and discursive devices used in language related episodes in their performances. the first research question was about evaluating the potentiality of four task types in directing students’ attention to syntactic devices. correspondingly, one way anova was utilized to test the first research hypothesis. the second research question was answered using one way anova to evaluate the potentiality of the targeted tasks in engaging students with intonational devices as a way to solve their communication problem. the third research question was answered using the same statistical technique to explore the potentiality of these four tasks in directing students’ attention to discursive markers. the fourth research question was answered by the microgenetic approach introduced by platt and brook (2002) and storch (2008). the findings show tasks are different in terms of their potentiality in engaging students with language at syntactic intonation and discursive levels whereas in terms of task engagement students went through the same patterns from pre-engagement to elaborate engagement across four task types. the findings imply a theoretical implication. level of task-ness is analyzed mostly on the basis of the essentialness, naturalness and utility of the linguistic elements that each task creates a medium for the occurrence of those elements. what is missing from this model is the level of task engagement. each task’s potentiality in engaging students with itself can create a medium for acquisition rich processes. the findings of the present study have important implications for language teaching, language testing and materials development. pedagogical implication suggests that the mere incorporation of tasks in the curriculum will not satisfy the principles of task- based and sociocultural approaches towards language teaching because the medium in which the interaction takes place will affect the quality of talk and in turns the quality of learning. the findings also provide insight to the concept of authenticity in materials development and testing as the findings support authenticity as a process rather than a product.