“The only place where feedback on error is typically present with high frequency is the language classroom. Even there, it is not always provided consistently. In Chapters 5 and 6, research on the role of feedback in the classroom will be reviewed. One condition that appears to be common to learners of all ages—though not in equal quality or quantity—is exposure to modified or adapted input. This adjusted speech style, called child-directed speech in first language acquisition, has sometimes been called foreigner talk or teacher talk depending on the contexts of second language acquisition. Some people who interact regularly with language learners seem to have an intuitive sense of what adjustments they need to make to help learners understand. Of course, not everyone knows what adjustments will be most helpful. We have all witnessed those painful conversations in which people seem to think that they can make learners understand better if they simply talk louder!”