In The Language Teacher, March/April 2010’s “Readers’ Forum”, Eric Bray writes about role-play in EFL (PDF, login and password required) (the TLT homepage mistakenly attributes the article):
Unlike more controlled language learning activities, roleplays [sic] are tasks which fall towards the freer end of the language learning activity continuum discussed by Nunan (2004) and Richards and Rodgers (2001), and give students practice accessing their current language resources. This builds fluency…
However, Krashen noted that a corollary of his input hypothesis is
Talking (output) is not practicing
Krashen stresses yet again that speaking in the target language does not result in language acquisition. Although speaking can indirectly assist in language acquisition, the ability to speak is not the cause of language learning or acquisition. Instead, comprehensible output is the result of language acquisition.
The article includes no evidence that roleplay helps students to develop fluency, although it does suggest ways in which it might “indirectly assist in language acquisition”.
if roleplays are set up carefully, students can get useful practice in situations they are likely to encounter abroad, while developing fluency and the confidence to deal with the unpredictability inherent in real world language use…
Indeed, Bray admits that “students must have adequate language ability to be successful with role-play”.
In Margarete Wells’ December 2008 review (PDF, login and password required) of Bray’s roleplay textbook (link to the publisher’s info page for this book), we find
the language of some instructions and model materials… is very high for EFL students… learners whose level is at least low intermediate, but preferably higher, would stand to gain the most in terms of increased confidence and improved proficiency, by using this book. The course relies heavily on learners being willing to think on their feet and be linguistically creative, not to mention the heavy stress on question techniques, which would seem to be very demanding for lower level students. (Margarete Wells, “Moving on With English: Discussion, Role Plays, Projects”, The Language Teacher 32,12 (December 2008): 21)
Even her post low-intermediate students “needed considerable input in terms of language and ideas”. This would seem to indicate that, in order to do these roleplays, students already need to have acquired a certain fluency, which undermines Bray’s claim, but supports Krashen’s view (see above).
In his conclusion, Bray points to what might be a strong motivation for a teacher to use roleplays (and by the way, Bray writes it as one word in his TLT article, yet in the title of his book the term is written as two, unhyphenated, words):
Finally, successful roleplays can transform the atmosphere of the classroom into a more fun and exciting place where anything can happen and probably will.
Now, I’m not against fun and excitement. However, teachers need to be clear on what their purposes and their priorities are, lest we fall into the trap of becoming illusionists. And we are still left with the problem of how to develop our students’ fluency.