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<Paper uid="W97-0507">
  <Title>I Using NLP in the design of a conversation aid for non-speaking children</Title>
  <Section position="4" start_page="43" end_page="43" type="metho">
    <SectionTitle>
2 The pragmatics of children's
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    <Paragraph position="0"> conversations McTear (McTear, 1985) has examined the pragmatics of children's conversations. The main pragmatic structures he notes are: greetings, initiations, attention getting, attention directing, conversation repair e.g. repeating an utterance or requesting or responding to a need for clarification, and use of discourse connectors for topic shift or to continue the conversation after repair and to signal turntaking.</Paragraph>
    <Paragraph position="1"> 'Ihrntaking exchanges can be to initiate, respond, follow-up or conduct a simultaneous response with initiation (e.g. &amp;quot;Is it in the cupboard&amp;quot; in response to &amp;quot;where is it?&amp;quot;). Even young children use verbal and non-verbal means to accomplish these activities as well as changes in prosody and variations in politeness depending on the partner. We are interested in investigating ways in which we can assist children in carrying out these activities by using prediction within PICTALK's organisation structure to reduce the complexity of the process required for finding the next appropriate utterance.</Paragraph>
  </Section>
  <Section position="5" start_page="43" end_page="43" type="metho">
    <SectionTitle>
3 PICTALK for Children
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    <Paragraph position="0"> PICTALK has many features that support the above activities. These include the use of pre-loaded text, a menu controlled organisational structure that models conversation flow and additional items specifically designed to keep the flow of conversation going. There may be a potential for NLP to contribute to the enhancement of these and other aspects of the PICTALK system.</Paragraph>
    <Section position="1" start_page="43" end_page="43" type="sub_section">
      <SectionTitle>
3.1 The role of pre-loaded utterances in
</SectionTitle>
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    </Section>
  </Section>
  <Section position="6" start_page="43" end_page="45" type="metho">
    <SectionTitle>
PICTALK
</SectionTitle>
    <Paragraph position="0"> The PICTALK system allows the user to pre-load potential conversation fragments that may be useful in some future conversational interaction. The substantive content of these fragments may be input with a particular interaction and a specific conver-Sational partner in mind or it may be more general for use with any of a number of potential partners.</Paragraph>
    <Paragraph position="1"> This pre-loading process may be very slow but it can be carried out whenever the user has time to do it and under circumstances when there will certainly be much less time pressure than during actual conversation. The intention is that the user will be able to access these pre-loaded utterances quickly during the conversation. Such rapid access is likely to be very important in social conversation. Experience with the TALK system (Todman and Lewins, 1996) suggests that the rate of conversation has a strong positive relationship with the ratings of satisfaction made both by a TALK user and by her conversation partners.</Paragraph>
    <Paragraph position="2"> Pre-loaded utterances currently have to be constructed by someone other than the PICTALK user Each of these utterances needs to be considered very carefully for several reasons. First, PICTALK holds very few (typically two dozen) utterances. As already mentioned, this is partly because few pictures can be accommodated on a fixed size of computer screen. Additionally, it is important that the cognitive demands made of PICTALK be limited and, therefore, the number of possible decisions that are required in order to select utterances must also be limited. Finally, PICTALK users are likely to have difficulty deciding how to make the conversation flow when the utterance they would like to use is not available.</Paragraph>
    <Section position="1" start_page="43" end_page="43" type="sub_section">
      <SectionTitle>
3.2 Selecting pre-loaded utterances
</SectionTitle>
      <Paragraph position="0"> It is generally considered highly desirable to allow people with disabilities to be as independent as possible. In this context, it would be desirable to allow PICTALK users to take more control over the content of their social interactions. Though at present utterances are developed and pre-loaded by someone other than the PICTALK user, the PICTALK system has a facility to allow the end user to select from a database of those available utterances and their associated pictures. Because the association between picture and utterances is imprecise, the user will need to experiment with the available items to see what speech is associated with each available picture before deciding whether to load an item into their PICTALK system. It would be helpful to offer first the items that are most likely to be appropriate. A wide range of conversation attributes could be used to predict the most appropriate utterance, e.g. the anticipated conversation partner, phrases selected for similar conversation partners, content related to the last phrase selected. Even a fairly small database of additional items with individually selected and stored attributes could offer benefits to these users.</Paragraph>
    </Section>
    <Section position="2" start_page="43" end_page="44" type="sub_section">
      <SectionTitle>
3.3 Supporting variations in conversational
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      <Paragraph position="0"> style At present it may be possible to support some variations in conversational style as a function of who the conversational partner is (e.g. peer, teacher). The simple solution is to address this problem when utterances are constructed for the user with a particular conversation partner in mind or when utterances are selected during a conversation. For example, in PICTALK variations in style can be expressed in the</Paragraph>
      <Paragraph position="2"> four utterances that are available to open a conversation (e.g. hiya; howdy; hello ) and the four other utterances that are available to close a conversation (see you later; goodbye; see ya ). It may be possible to provide more general support for variation in style either by picking up the cue to style from the opening utterance selected and then using the corresponding variation of each subsequent utterance selected or by offering suitable prediction when the user selects material from a database of utterances in preparation for an interaction with a particular class of conversation partner e.g. polite style for adult, more informal style for classmate.</Paragraph>
    </Section>
    <Section position="3" start_page="44" end_page="44" type="sub_section">
      <SectionTitle>
3.4 Accessing material through the
</SectionTitle>
      <Paragraph position="0"> organisational structure Most of the utterances available to the PICTALK user are organised in a shallow menu structure. There is a hello menu button to give access to greeting utterances, a goodbye menu button to give access to closing utterances and most of the remaining content is accessed through a set of 3 intersecting perspectives, namely, person with 2 values: me and you; tense with 2 values: past and present/future and affect with two values: happy and sad. By selecting one each of these three perspectives, the user gets access to pre-loaded content appropriate to that combined perspective e.g. content on something I like doing (me/present/happy).</Paragraph>
      <Paragraph position="1"> These perspectives are designed to support the flow of conversation and require only one button press to move from phrases about what I disliked (me/past/sad) to phrases about what you disliked (you/past/sad) or from phrases about what I liked (me/past/happy) to phrases about what I would like (me/present/happy). With similar features, TALK has been shown to support its users in initiating conversation topics and in turn-taking in the Question-Answer format (Todman et al., 1994b). Unfortunately, our experience with PICTALK users suggests that this menu structure is very difficult for them to understand. It may, however, be possible to support the PICTALK user by predicting and suggesting suitable utterances during a conversation.</Paragraph>
      <Paragraph position="2"> From McTear's (McTear, 1985) work, it seems plausible that children may be able to recognise a suitable utterance (identified by its associated picture) as appropriate if it were suggested, even if they are unable to recall and locate it. Though it would be difficult to implement, a modestly effective prediction system could reduce the cognitive load on the PICTALK user. Such a prediction system may be easier for children than for adults. Some theorists, notably, of course, Piaget (Piaget, 1959), have suggested that children are more egocentric than adults in all aspects of social relationships including conversations, by which it is usually taken to mean that they respond less to the listener's perspective. While later work has suggested that the level of egocentrism which is in general exhibited by young children may not be as great as suggested by Piaget e.g. (Selman, 1980) nevertheless the ability to make this type of social adaptation is not fully developed for some years and therefore children may be less responsive to their partners (McTear, 1985). This may have the fortuitous consequence that the child's next utterance depends more on the child's last utterance, which is known by the system, rather than on the partner's last utterance, which is not known.</Paragraph>
    </Section>
    <Section position="4" start_page="44" end_page="44" type="sub_section">
      <SectionTitle>
3.5 Keeping the conversation flowing
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      <Paragraph position="0"> PICTALK provides a few other utterances that are outside of the menu structure and are always available. The utterances are intended to support the goal of maintaining conversational flow when a suitable specific response to something a partner says is not available and fulfil general pragmatic functions such as initiation to get attention, e.g. &amp;quot;Hey!&amp;quot;, repair when something has gone wrong, e.g. &amp;quot;OOPS&amp;quot; or &amp;quot;What?&amp;quot; or &amp;quot;I don't have anything to say to that&amp;quot; and discourse connection to signal a topic shift, e.g.</Paragraph>
      <Paragraph position="1"> &amp;quot;Now, right&amp;quot;. Utterances can also be available support the speaking conversation partner. In using the TALK system, we have found that keeping the partner informed in some way is reassuring and helpful.</Paragraph>
      <Paragraph position="2"> They need to know, for instance, that a longer than usual silence is not signalling the termination of the interaction and this can be achieved through the inclusion of such utterances as &amp;quot;hang on. I need to find what I want to say&amp;quot;. It may be that some of these may be automated. For example, it might be possible for the PICTALK system to recognise that its user is searching for something to say when con: secutive menu presses are made or even to recognise that a topic shift is being initiated when the utterance just selected differs greatly in semantic content from the previous utterance.</Paragraph>
    </Section>
    <Section position="5" start_page="44" end_page="45" type="sub_section">
      <SectionTitle>
3.6 Training
</SectionTitle>
      <Paragraph position="0"> Children who have no speech or whose speech is so impaired that they cannot be readily understood may not have had opportunities to develop a familiarity with the structure and pragmatics of conversational interactions nor the skills required to maintain them. They also need considerable training to use the PICTALK system effectively. Therefore, we are developing a training system to help such children develop their conversation skills with PICTALK. In  the training system, the computer, using one speech synthesised voice, converses with the child, using another speech synthesised voice. At present the script for the computer is entirely pre-programmed. It might be possible to introduce intelligence into the script to allow the computer to respond appropriately to a wider range of user's contributions. Such a system should make it easier to retain the child's interest during the rather long training period. Because each of the child's responses is known to the system and is predictably limited to those available in PICTALK, it might be possible for the computer to converse fairly naturally with the child.</Paragraph>
    </Section>
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