Communication acts

The communicative function or illocutionary force of each utterance or nonverbal communication signal was coded, according to the principles of speech act theory

originally developed by Austin (1962) and Searle (1969). If utterances contained more than one part (see above) they were segmented into their constituent parts and each part was coded for its communicative function, as in Chapman (1981). Each segment of an utterance or nonverbal signal coded is termed an "act". This multi-functional approach was taken in an effort to code the illocutionary forces intended in the interaction, rather than the "head" function only which may conceal differences in conversation patterns between the groups, and to maximise reliability of coding (van Kleek, Maxwell & Gunter, 1985). The assignment of act function was made taking into account the literal meaning of the communication signal, the nonverbal signals accompanying verbal/vocal utterances, the activity in which the speakers are involved, the response of the listener and the preceding and subsequent acts in the conversation, following Dore, Gearhart and Newman (1978) and McTear (1985).

The acts in the taxonomy used were chosen from previous research into the interaction of non-disabled and disabled children with familiar and unfamiliar adults (Gallagher, 1981 ; Light et al, 1985b; Wetherby et al, 1988) to reflect the intention of the speaker. A limited number of acts were selected under which subgroups of act types may be subsumed, in order to increase coding reliability and to observe interaction patterns (McTear, 1985). For example, request for information in this protocol subsumes Wetherby and colleagues* (1988) request for permission. Attempts were made to avoid the semantic and structural categories found in some speech act coding systems, which may shift the focus of attention from the purposes of communicative signals towards their syntactical forms or how they serve to structure conversation. The reliance upon syntax to assign codes was thought to be additionally unsuitable for the present study due to the high proportion of

single word utterances expected and possible telegrammatic utterances produced by children using AAC. This lead to the rejection of several published protocols (eg. Coggins & Carpenter, 1981; Dale, 1980; Dore, 1974, 1978; Dore et al, 1978).

In spite of attempts to exclude semantic categories in the protocol, the category "confirmation/denial" was included, as previous studies have shown frequent use of yes/no questions to non-speaking individuals (eg. Harris, 1982; Light et al, 1985b). Previous research also prompted the inclusion of subordinate categories for requests for clarification; confirmation, neutral and specific; and provisions of clarification: repetition and revision. A high incidence of communication breakdown has been noted in conversations between aided and natural speakers (eg. Collins, 1994), and it has been observed that non-disabled children produce different responses to answer individual types of requests for clarification (eg. Anselmi et al, 1986; Shatz & O'Reilly, 1990). As it is not clear from current research if particular types of requests for clarification are frequently used in conversation with physically disabled children, or if the children favour certain types of responses, each subordinate category was included in the protocol. The acts included in the taxonomy are shown in Table 4, with their definitions and some examples of each act.

Table 4 Acts used in the study

Function Definition Exam ple

Request for joint attention (RJA)

the attraction of a listener's attention to speaker, activity or obiect

"Look", leaning/reaching towards and object and then looking at Ustener (or vice versa) Request for information

(RI)

the seeking of knowledge about objects, activities, people, internal states etc. through indirect or direct questions, except requests for clarification

vocahsations containing rising intonation produced

before/afterAvhilst child looks at Ustener quizzically, pointing to question symbols, open and closed questions

Request for object/action (ROA)

asking hsteners to perform an action or to give the speaker an object

reaching towards an object and looking from the object to the Ustener, pointing to a symbol denoting an action, signing the name of an object

Request for clarification:

Confirmation (RCC)

Neutral (RCN)

Specific (RCS)

seeks repair when a message has been misheard or misunderstood encodes "is this exactly what you said?"

encodes general lack of understanding or that none of message has been heard part of message only needs to be reproduced, part has been heard

"You want the book?", repeats original message questioningly "What?" "Pardon?" "I didn't hear you/don't understand"

"You want the what?"

Provision of clarification:

Repetition (PCRep)

Revision (PCRev)

attempts to make clear one's original message

reproduces original message using same words, symbols, gestures conveys same meaning but change words, symbols, gestures etc. used

See Appendix 2

Provision of information (PI)

comments on situation, people, internal states

"I feel sick", "He's coming by car", "It looks like rain " Expression of self

(ES)

sharing of feelings, emotional states, showing personality

lau^iing, protesting, sarcasm, telling a ioke

C onfirmation/Denial (CD)

conveying agreement/ disagreement with other's statements/actions etc.

"Yes". "No", "I think so"

Acknowledgement (AK)

responses to what has happened/ been said but provide no additional information

"Oh". "Good boy". "That's it ", following child's action

Unintelligible (Unint)

any message not understood by listener or rater

NB. Examples given in speech marks can be produced verbally or via AAC systems. (Definitions for, and further examples of each act type are given in Appendix 2 .)