^{Several published courses make use of a technique often called the 'open dialogue’. This essentially consists of a dialogue with one character's remarks missing; the student has to supply the missing parts, sometimes from a written text, sometimes from a tape. An example might be the following:}

^{John: Hello Mary,}

^{Mary: ...........}

^{John: Where have you been lately? I don't seem to have seen you about.}

^{Mary: ………}

^{John: Goodness, that must have been fun.}

^{Mary: ………}

^{John: I see. Well what are you going to do now?}

^{Mary:...........}

^{John: Really? That's interesting. Well I must be off now. Goodbye.}

^{Mary: ………}

^{Thus the student has to supply a sequence of utterances by one of the characters in the dialogue; what he or she says can either be pure imagination or can be based on general knowledge of the characters in the course, or can be a paraphrase of information that has already been presented in another form, say in a text about Mary's holiday in Florida.}

^{What does this kind of exercise teach? Obviously it is a form of production in that the student has to produce sentences rather than to imitate or read them aloud. The student does not have an exact model of what to say but his sentences are constrained in their range of structures and vocabulary by the situation implicit in the particular dialogue: Mary seems to be on friendly terms with John and so her replies are going to be in an informal conversational style; they are also confined to the expression of her recent experiences and future plans, apart from formulaic greetings. Yet this is not 'true' production because it is not communicative; the process of speech production starts from an idea, an intention to say something, in the mind of the speaker. The open dialogue starts from an attempt to roleplay the mind of someone else; what might Mary actually have been doing? Hence the open dialogue does not usually involve the student's own ideas and opinions; it is imaginary production rather than real production.}

^{The other teaching point is some aspects of conversational interaction. Conversation is a continuous negotiation between the participants: one person decides to say something, the next decides how to answer; this alters the course of the conversation so the first person decides to say something about the new topic, and so on. Conversation is made up of chains of 'interaction sequences; in the example John starts with a greeting 'Hello Mary’ to which the accepted reply is another greeting. He goes on with a general news enquiry,; it is usually up to the person who opens the conversation to make some general conversation starter, particularly on the telephone. Mary gives an explanation and John responds with his reaction 'Goodness, that must have been fun’, calling for an amplification from Mary. John acknowledges this with 'I see’ and then plays the ball back to her by asking her future plans. After she has answered he reacts, 'Really? That's interesting', gives a pre-closing remark 'Hell I must be off now’ and a final exchange of 'Goodbye’ takes place. Each of these moves take place in sequence; the reaction 'Really?' cannot precede the statement to which it reacts; the pre-closing 'I must be off now’ has to precede the final closure 'Goodbye'. However, though in a real conversation the conversational moves follow a definite sequence, the participants have a range of alternative moves they can choose from at each point; in other words, the interaction sequence is a flexible sequence of choices rather than a rigidly followed track; Mary could for instance have answered "Where have you been lately?" with 'None of your business’, provoking a different reaction from John and a premature closing of the conversation. So as well as the 'functions' with which we are all now familiar an important aspect of conversation is sequences of functions; we can't use 'requesting' without seeing what comes after 'requesting’ - 'acknowledging, declining, fulfilling' and so on. The open dialogue therefore provides a model of an interaction sequence; the student has to decide the appropriate move at each point in the conversation; he is learning that statements require reactions; greetings return greetings. So, taking this together with the preceding point, in an open dialogue the student is practising adapting the structures and vocabulary he knows to the fluctuating demands of a conversation; he is practising certain strategies for discourse.}

^{Valid as these aims may be, there are some difficulties in achieving them within the open dialogue. The chief difficulty is the essential unpredictability of conversation: we cannot tell exactly what someone is going to say next in structure or vocabulary even if we can predict certain typical sequences. Suppose that the student answers John's question "Where have you been lately?" with "Having open heart surgery", then John's next remark becomes inappropriate 'Goodness that must have been fun’. Anyone who has taught with open dialogues knows that this kind of problem is far from rare: few open dialogues do not go adrift at some point. One standard way of preventing this is to give the students access to the whole dialogue: they read through the dialogue first so that they have an idea of what is coming as well as what has gone by. Though this solves the problem in a superficial way since they can now produce appropriate remarks, it does rather go against the teaching aims; we do not normally have access to what people are going to say in half a minute's time and so the student is not getting practice in normal conversational strategies. The other standard way of preventing unlikely sequences is to make the existing remarks so neutral that they can fit almost anything the student can supply. Thus John's "I see" fits almost any response of Mary's to 'That must have been fun'; he then hurriedly changes the subject "Well what are you going to do now?" and answers her reply with another neutral phrase "Really? That's interesting"; even the response 'that must have been fun' has ' something of this fence-sitting quality about it since it could, in the written form, be ironic, even if on tape the intonation would probably preclude it. So characters in open dialogues tend to give bland responses and to change the subject rather frequently; the model of conversation that is used tends to be rather unnatural, sounding more like an interview where it is indeed expected that the interviewer will not reveal his own reactions and will direct the conversation as he wishes. Both these problems are inherently due to the inflexibility of print and tape; the next part in the dialogue has to be printed or recorded in advance and cannot take account of all the variations that a student could introduce. It is possible that a more flexible type of open dialogue could be programmed on to a micro-computer where the responses reproduced by the computer could take account of at least some of the variations students are likely to introduce.}

^{However, perhaps the teacher may be able to adapt open dialogues to overcome these problems. One technique is the 'crossover dialogue1 which combines some aspects of the communication game and some of the open dialogue. The essential feature is to have two versions of the dialogue, on different sheets of paper. For instance, one page might have the following:}

^{On another page there is the other version of the dialogue.}

^{The students use this in pairs, one looking at Version A, the other at Version B. First they read aloud the dialogue on the left, each reading the part on their page. Then they transfer to the dialogue on the right. This time it is essentially the same dialogue personalised to their own characters.}

^{The overall advantage of the crossover dialogue compared to the open dialogue is that it eases the students gradually in to what they have to say.}

^{1,   It provides a model. Instead of having no idea what the correct move is in the dialogue at any particular point, the student has practised precisely that move and can incorporate his own information into the model. Instead of being left to his own devices the student can always fall back on the model given on the lefthand side of the page.}

^{2.   It can relate to real communication. The student starts from the fictional conversation with imaginary characters but transfers to a 'real' conversation in which he plays himself talking to someone else. Thus the crossover dialogue seems to involve more active involvement by the students in that they are having to choose what they themselves want to say, within the framework of the conversation, rather than putting arbitrary words and opinions in their own mouths.}

^{3. The language can be more of a real conversation. Since the students have been through the dialogue, reading their parts aloud, they know what is coming in a sense. But they know this only in the terms of the structure of the conversation, not in terms of the specific content or the particular moves of the other speaker: they know the overall interaction sequence. Thus they are prepared for what is coming in a general sense, but have not had the detailed preparation involved in seeing the whole of the other person's remarks in writing before they have to speak. So the crossover dialogue, to some extent, avoids the problem of the unpredictability of conversation encountered in the open dialogue in that it gives the students a skeleton but not the actual flesh.}

^{The teacher may adapt most published open dialogues in this way by typing out the two sides of the conversation on different sheets of paper and then by producing two fill-in versions of the dialogue on the same two sheets using the students own experiences. The advantages are that the teacher is removing some of the problems while at the same time increasing the communicative aspect. Such dialogues are also easy to construct oneself, either from imagination or by taking any printed dialogue with two parts and typing it out as described above. Indeed an advanced exercise might involve the students themselves constructing such dialogues. Open and crossover dialogues are useful techniques for controlled conversation as part of a methodology that emphasises not just functional communication but the development of interpersonal skills.}