SL has a number of functions to be utilized for language learning:

Using these SL functions, it is possible to set up the environment with objects such as schools, classrooms, desks, and chairs necessary for a formal learning environment, and shops, parks, streets, etc., used for communication tasks in an naturalistic environment. In this environment, leaners can engage in various activities, such as exchanging text messages, listening to the recorded sounds, giving and taking things to/from other avatars and objects. In addition, it is possible to control these created objects and their actions by adding script command.

Thus, using LSL, you can embed in agents:

and you can make agents respond to an avatar´s speech and actions by text-messaging or playing recorded sounds/voices.

In second language teaching, meaning-focused lessons and activities are emphasized. This was a reaction against insufficient learning outcomes of form-focused type of teaching adopted in the Grammar Translation method and the Audio-Lingual approach. Many language teachers adopt the Communicative Language Teaching (CLT), which has been one of the most influential language teaching methodologies. CLT emphasizes meaning, and as effective activities to improve communicative ability, communication tasks are recommended to be used. Communication tasks “hold a central place in current SLA research” ( Ellis, 2003 ). Thus, Task-Based Language Teaching is being advocated and language teachers are trying to introduce communication tasks in their lessons. The definition of a communication task varies among researchers and practitioners, but its essential characteristics are common. The present study, based on the definition by Skehan (1998), defines the constituents of a task as follows:

In communication tasks, various types of interactions occur and learners often have difficulties understanding what their interlocutor says. This kind of misunderstandings occurs especially when the interlocutor makes an error in the use of the language. The interactions occurring in these occasions have been discovered to have specific patterns. Varonis and Gass (1985) showed an example of conversational exchange to explain the structure of the interaction, which has two stages: a trigger and a resolution. The former stage, trigger (T), involves a remark that causes a comprehension problem. The latter stage consists of an indicator of a problem (I), a response to the indicator (R), and an optional reaction to the response (RR).

Student 1: And what is your mm father´s job?
Student 2: My father is now retire. (T)
Student 1: Retired? (I)
Student 2: Yes. (R)
Student 1: Oh, yes. (RR)
( Varonis and Gass, 1985 )

The Interaction Hypothesis states that the discourse work to resolve this type of non-understanding sequence is called the negotiation of meaning. In the negotiation of meaning, varieties of conversational strategies are used in the exchange, among which “Comprehension Checks,” “Confirmation Checks,” and “Requests for Clarification” are used very often. The use of these strategies leads to more positive evidence about the correct target language forms. Recasts, which are rephrased learners´ utterances by changing one or more sentence components, are also used.

The results of the Interaction Hypothesis research argue that the negotiation of meaning using these strategies, combined with the contribution of negative feedback (e.g., when a second language learner makes an error using the past tense, such as saying “He come yesterday,” a native speaker will say, “You have to use the past form when you say ‘yesterday’.”), modified input (i.e., foreigner talk and teacher talk, which are simplified versions of a language), and comprehensible input (i.e., input of a slightly higher level than the learner´s present proficiency level), facilitates language acquisition.

Thus the incorporation of these two theories, the Task-Based Language Teaching and the Interaction Hypothesis, can lead to the construction of learning environments that efficiently promote language acquisition. This is possible because learning in this environment entails communication tasks, especially the ones where meaning negotiation occurs with appropriate feedbacks from the interlocutors.

In order to incorporate the task structure into SL, the structure of a typical task conducted in a classroom was analyzed. A task performed in a classroom consists of three parts. The first part is an explanation of the task procedure by an instructor. The instructor provides an explanation of how the task proceeds by using a handout. Consider, for instance, a shopping task, which is an example task used in this study. Before starting a task, learners are explained as to where they are going, what they are going to buy, and how much money they have. The second part, which is the main part, is where the task is actually performed. In the case of a shopping task in a real classroom, learners interact with each other by forming, for example, two groups and taking either the shopper's role or the shopkeeper's role. The third and last part is where learners exchange information about what they have done. In the case of a shopping task, it will be the information about what they bought and how much they spent on shopping. This is usually done by way of presenting the goods they have obtained or reporting what they have done to the teacher or the whole class.

These three parts can be incorporated into an equivalent number of SL components. They are the initiation component, the task component, and the evaluation component. The initiation component is where the explanation of a task is given by an agent placed in a virtual classroom and embedded with recorded explanatory voices and text messages that are presented to learners in response to a learner´s utterance. The task component is where learners perform the task while interacting with an agent. This component has its own specific space containing items needed to conduct the task. In the case of a shopping task, a shop is built with target goods placed inside, where learners go, assume the role of a shopper, and interact with an agent to buy what is requested in the initiation component. The evaluation component is where learners report to an agent the task outcome or show what they have obtained (Figure 2).

Figure 2 Incorporation of task components into SL

The previous chapter introduced the design to incorporate the SLA theories, i.e. the incorporation of the task structure, the interaction structure and the mechanism of meaning negotiation. The next step is to implement the design into SL and to construct AITS. Following is the implementation method of the task structure.

Figure 5 the initiation component

Figure 6 the task component

Figure 7 the evaluation component

Figure 8 Classroom A and B

As stated above, there are three components in the task structure. The first is the initiation component called Classroom A (Figure 5), where a teacher agent, called Dick, instructs a leaner about what to do and provides necessary things to perform the task. In the case of a shopping task, the learner is instructed to follow the directions shown and go to a shop, buy three apples, and then go to neighboring Classroom B to report the outcome. The second component is the task component, or the space for the main task (Figure 6). This is where the learner performs the designated task by interacting with an agent prepared specifically for the task. If s/he succeeds in the communication with proper motions, s/he can successfully pass through this component. In case of a communication breakdown, the above-mentioned interaction sustaining mechanism begins functioning to help modify the learner´s utterance. The last component is the evaluation component which is Classroom B (Figure 7), where another agent teacher called Eve evaluates the outcome of the task. The learner is asked to show what s/he has obtained in the task. If s/he can successfully answer her questions about the content of the conversation between the learner and the agent in the task component, the task is completed. This task structure would be valid to any other types of task, such as “Showing the way”, “Eating at a restaurant”, etc.

Figure 9 demonstrates the simplified LSL description of the interaction structure and the mechanism of the negotiation of meaning at the start of the conversation in the task component ( section 5.2.1. ). Each state consists of one I-Unit and (if necessary) the embedded mechanism of the negotiation of meaning. The agent´s responses can be easily controlled by changing the contents of the messages (message 1 and 2, in this example). Furthermore, the difficulty level of the conversation task can be coordinated by changing the expected contents of the learner´s utterances (utterance 1 and 2, in this example).

Figure 9: Simplified LSL description of the interaction structure and mechanism of the negotiation of meaning

Thus the agents are programmed that they always watch or listen to learner avatars approaching or chatting text messages, and this makes them respond and react to learner avatars as soon as they notice them approaching or they type any strings of letters. Thus, if a learner enters the initiation component, or Classroom A (Figure 5), and approaches Dick, he starts to speak to him/her, “Hello. I´m Dick. What´s your name?” If an agent in the task component notices a learner type a phrase like “have apple(s)”, he replies using recorded voice like “How many would you like?” In addition, learners perform the task not just by communicating with the agents but by experiencing as they usually do in the real world; taking and giving objects such as goods and money. In the same way in the evaluation component or Classroom B (Figure 7), Eve starts to say, “Hello. What did you get?” when she notices a learner approach.

Ten university students participated in the experiments. The purpose of the experiment was to investigate the usefulness and the deficits (if any) of AITS, by examining the number of occurrences of the negotiation of meaning during the conversation, whether learners completed the task, how long it took to complete and what their evaluations were after the experiment. Individual participants came to the research room and experienced AITS by operating an avatar prepared by the authors. First, they were given an explanation about the experiment, what they should do to complete the task and how they should operate the avatar before the task. After the experiment, a post-survey questionnaire was used to evaluate AITS. An assessment device to record users´ logs was installed in a remote server to analyze the quantitative data: task completion, the number of occurrences of the negotiation of meaning and the time needed to complete the task.

Based on the analysis of the recorded log in the assessment device, six out of the ten participants completed the task and the average completion time for the task was about 12 minutes. Of the six participants who completed the task, two succeeded without using the negotiation of meaning. They seemed to have no difficulty understanding the agents´ utterances and, after only one listening, completed the task without any communication breakdown. The other four successful participants completed the task using the negotiation of meaning. Of the four participants who abandoned the task, three did not try to negotiate the meaning and as a result had to stop the learning process. This was probably because they had not acquired strategies that should be used in case of communication problems. One participant tried to negotiate the meaning, but did not receive beneficial feedback because he erroneously typed “perdon” instead of “pardon.” As for the task component, or the main task component, only one participant managed to use the meaning negotiation strategy.

The results of the survey shows that more than 70% of the participants thought learning on AITS was interesting as well as difficult, and that they would like to learn on AITS again. More than 50% of the participants felt learning on AITS was more fun than learning in a classroom; however 40% of them thought that this method of learning could not be said to be more effective. This result can be interpreted that AITS promoted motivation for learning because of its immersive nature despite the task being difficult. However, it still has a challenge to be solved in terms of learning effects. It should be also noted that out of the four participants who failed, two answered that operating the avatar was too difficult and did not understand what they should do. This is related to technological problems and confirms previous research results ( Hislope, 2008 ; Cooke- Plagwitz, 2008 ).

The free-text descriptions about the advantages of AITS indicate that the merits of AITS are its life-like virtuality, autonomy and ability to provide repeated responses to learners. The followings are some examples of the descriptions.

Q: What are the advantages of AITS?
Participant A: I was able to freely operate my avatar and learn English with pleasure.
Participant B: I was able to study as if I were in a foreign country and it was possible to freely move my avatar around.
Participant C: I was able to ask for agents‟ repetition as many times as I wanted, so I understood what I would do next.
Participant D: The situation was realistic and I thought I could apply the experience to the real world.