In our preliminary investigation, we analysed videotaped sessions of
adolescent word board users describing pictures to their speech
therapists. Our goal was to observe patterns of verbal and gestural
communication in these sessions, and to consider how they may reflect
more general features of augmented conversation. We identified a
number of interactional features, including cooperative construction
("co-construction") of sentence meanings, word-finding, and
conversational repair, by both participants in each session.
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Contributors
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Conversation is often a cooperative, bi-directional, and multimodal
process of constructing and exchanging information. In the context of
AAC, a conversational partner often becomes actively involved in
constructing the augmented speaker's message. The partner may ask
questions, repeat part of the augmented speaker's utterance, or simply
nod and smile in agreement. This feedback may in turn affect the
message being produced by the augmented speaker.
Computer-based AAC systems currently "see" only the words the
user selects. The less information the user provides as input, the
less the likelihood of accurate output. Studies with manual AAC
systems suggest, however, that other modes of communication may be
preferred. For example, children with cerebral palsy chose to use
vocalizations, gestures, or eye gaze as modes of communication far
more often than their manual symbol boards in interactions with their
mothers or their speech therapists. These alternate modes of
communication may be critical to fully understand augmented
interactions. Already, the use of gestural recognition is being
considered for future AAC systems.
This pilot study is our first step in defining design criteria
for an augmentative communication system that provides common
interactional features of a conversation involving a person using a
communication aid.
Four adolescent students with cerebral palsy and their speech
therapists took part in this study. Each student used a manual word
board to describe pictures in a storybook to their therapist, as if
telling a story to younger children.The therapist was instructed to
repeat each word as it was selected, and to paraphrase the student's
sentence when it was complete. These sessions were originally
recorded for van Balkom et al. (in preparation).
Several modalities of student and therapist communication were
transcribed, including vocal productions (both words and non-words),
hand and arm gestures, facial expressions, and head gestures.
(a) Repetition by listener. Contrary to
instructions, therapists often interpreted students' utterances before
the student finished the sentence. The interpretations could be
described as varying along two dimensions: incrementality and
compansion.
An incremental interpretation is one during which the listener
repeats the entire sentence so far. In a compansive
interpretation, the listener inflects the student's utterance and adds
function words.
In the following example, the student produces the words 'boy',
'girl', and 'walk' (in italics). The therapist (in bold)
might respond as follows:
(a) Transformations consistent with Compansion.
Therapists performed "standard" Compansion transformations on
students' utterances, such as adding missing function words and
appropriate syntactic affixes (e.g. tense markers). As well,
Compansion is currently able to perform such observed transformations
as changing the word order in a sentence, inferring a missing agent or
verb, and adding conjunctions.
(b) Transformations beyond the scope of Compansion.
Therapists were able to drop or replace inappropriate words from an
utterance, possibly using more than just the linguistic context. They
could infer which verb should be used, if no verb was given by the
student. In most cases, Compansion cannot perform these
transformations.
Therapists were privy to information that was not available to
Compansion. For example, in some cases the therapist appeared to be
making use of the student's gestures, objects in the room, or pictures
in the storybook to disambiguate an utterance, none of which are
available to the Compansion system. In other cases, therapists may
have used their knowledge of the world to infer what the student had
intended to say.
The purpose of this pilot study was to help identify issues relevant
to natural conversations and AAC systems for further investigation. As
a result, we are preparing a number of subsequent studies, listed in
the previous page, to pursue these issues
further.
McCoy, K. F., McKnitt, W. M., Peischl, D. M., Pennington, C. A.,
Vanderheyden, P. B., & Demasco, P. W. (1994) AAC-user
therapist interactions: Preliminary linguistic observations and
implications for compansion. In M. Binion (Ed.),
Proceedings of the RESNA '94 Annual Conference
(pp. 129-131). Arlington, VA: RESNA Press.
Vanderheyden, P. B., Pennington, C. A., Peischl, D. M., McKnitt,
W. M., McCoy, K. F., Demasco, P. W., van Balkom, H., & Kamphuis,
H. (1994). Developing AAC systems that model intelligent
partner interactions: Methodological considerations. In
M. Binion (Ed.), Proceedings of the RESNA '94 Annual
Conference (pp. 126-128). Arlington, VA: RESNA Press.
van Balkom, H., Kamphuis, H., Demasco, P., & Foulds, R. (in
preparation). Language technology in AAC: Automatic
translation of graphic symbols into text and/or synthesized
speech.
Interaction and Negotiation
Examining the transcripts, we found a number of interesting patterns
of negotiation and interaction between therapist and student.
(b) Word finding strategies. When a student did not
know a word, the student or the therapist often initiated some kind of
word finding strategy. Verbal/linguistic strategies observed included
selecting a synonym or related word(s), spelling the word, or giving
the first letter, or using an idiosyncratic word to signal a lexical
gap. As well, gestural strategies, such as iconic gestures or
pointing, were employed.
Implications for Compansion
Analysis of the transcripts also revealed information relevant to our
AAC design assumptions. Specifically, some of the interpretations that
therapists produced for a student's utterances were consistent with
our Compansion system, and some were
not.
[abstract], [text (13K)], [postscript (75K)]
[abstract], [text (13K)], [postscript (67K)]