Typically we choose not to give hot correction during speaking activities because we believe it interrupts the students' flow of thought and may embarass them in front of their classmates. Also, as Carol points out, 75% of communication in English is done by non-native speakers, and students should be able to deal with mistakes in what they hear.
Anyone preparing students for exams will know that the criteria for marking speaking usually allows any errors which do not impede communication. Actually, only certain errors have been proven to impede communcation. Those are, for example, the distinction between /p/ and /b/ at the beginning of words, and the difference between long and short vowels (a mistake I hear in almost all of our students in Russia). Interestingly, most consonant sounds cause problems if they are not pronounced properly, but not /th/, something we try to drill into our students in countries where this sound does not exist.
Those errors all deal with pronunciation. Well, what about grammatical errors? According to Numrich, Seidlhofer (2004) states that errors which do not impede are forgetting the 3rd person -s, confusing who and which, and misusing articles. There are others, but I have named these as they are errors which I feel usually have my colleagues and I tearing our hair out over. 'He's advanced, how can he still say "he do"!!' As if we didn't know that this particular mistake is one of the very last to be corrected in any learner, native or otherwise.
It is also difficult to know whether these mistakes are actually just slips, and correcting them might just frustrate our learners.
So perhaps we don't need to correct all these errors then at all?
Well, certainly many Russian students would have a very low opinion of their teacher if he or she just passed over all these errors. So which method should we use?
According to Carol's study, most teachers prefer to recast the student's mistake. It's fast and it's teacher-controlled, so the teacher can mentally pat himself on the back. 'I corrected this mistake!'
(For more info on types of error correction, Olenka Bilash's site has a very detailed summary. http://www2.education.ualberta.ca/staff/olenka.Bilash/best%20of%20bilash/error%20correction.html )
But apparently our students don't hear this as correction! When we recast the student's sentence, he understands it as clarification of meaning, not grammar. (The brain works in strange and wonderous ways.) So the student thinks the teacher didn't understand where he went, not the fact that he got his past simple wrong.
Two of the many problems that Carol mentioned connected to recasting are i) the teacher may not take into consideration the stage in the student's own development, ie. is he ready to perfect the 3rd person -s or is he still learning what a verb is at all? and ii) just because a mistake has been corrected, does it mean the student has actually learnt not to make this error?
If the teacher chooses to recast, we are recommended to keep it short and focussed on only one error at a time. We are advised not to raise our voice as we question their sentence, or the learner will think we are seeking clarification of meaning, rather than language. Instead, if we use a firm, flat intonation pattern, the unusualness of the teacher's voice will draw the student's attention to the fact that a mistake has been made.
But there are other options available to us. We could ask the student to clarify what he has just said. We could use metalanguage, if the student is able to understand the terminology: 'Is that 2nd Conditional?' We could elicit the correct version from the leaner or from the rest of the class. But most importantly, the correction should be explicit and immediate.
Bang goes cold correction. Haven't I just spent ten years teaching myself to collect mistakes for the end of the lesson instead of jumping in every time I hear a mistake?
Perhaps this week I'll try to get out of my groove and give hot correction every time. I wonder will my students notice? I wonder will they be offended? And I wonder will their accuracy be a lot better because of it? Let's see...
(Many thanks to Carol Numrich and Pearson Longman - this is not intended to be plagiarism, just my musings on the topic.)