[7] A leading theorist in his field of study, Ellis has focused much of his research on task-based language teaching (TBLT).
[13] In defining a task, Ellis draws off the definitions provided by others scholars (namely David Nunan and Graham Crookes) by focusing on the successful conveyance of language.
This distinction also affects the role of each participant, as a task requires students to act as language users.
Ellis maintains that despite the theoretical contributions made by Stephen Krashen, Robert DeKeyser, Michael Long and Bill VanPatten to the field of second language acquisition, there is no agreement on form-focused instruction or corrective feedback.
In 2004, he compiled a set of 10 principles of instructed language learning that have been considered and challenged by other SLA scholars.
[15] These principles include: The basis for this list is grounded in various theoretical perspectives, though namely the computational model of L2 learning developed by James Lantolf.
[17] The former is concerned with drawing the student's attention to linguistic form (including, but not restricted to, vocabulary and grammar) whereas the latter focuses on conveying messages.
[18] In taking note of the reconceptualization of focus-on-form by other scholars, notably Michael Long, Catherine Doughty and Jessica Williams, Ellis distinguishes between planned and incidental focus on form.
[20] Ellis suggests that explicit corrective feedback can be useful in the syntactic and other grammatical understandings in the target language by asserting and demonstrating the type of mistake produced in an utterance.
[25] The view that Littlewood has against Ellis's TBLT method is that the required knowledge of the target language must already be at a fairly proficient level in order to complete the tasks being carried out.
[21] Ellis explains that this is true on the basis that it is a production task; other gap-fill activities can be used by beginners.