ACQ Vol 11 No 1 2009

MULTICULTURALISM AND DYSPHAGIA

ing to spelling conventions (Leitão, 2001). For example, “horse” may be linked with other words spelled with “or” replacing the link with other words with the same rime but different spelling. Throughout development, links between related concepts/words form schemas or other efficient organisational systems for thinking and communicating (e.g., see Reynolds, Sinatra & Jetton, 1996; Rumelhart, 1980). A mature internal language system with multiple overlapping organisational systems is considerably more complex than can be represented in a drawing, so figure 2 only inadequately captures the increasing complexity by the inclusion of an arrow. Sophisticated neural organisation according to relevant features is the key to efficient retrieval of symbols (Camarata & Nelson, 2002). Highly sophisticated and easily accessible language symbols within efficient organisational systems are required for thinking and for literacy. Factors in the environ­ ment, the person’s genetic predisposition, the language context, and the person’s emotional state impact on how an individual forms, organises and accesses symbolic repre­ sentations (see figure 5). The environment is important in how/when/how many symbolic representations of concepts are formed. Thus, poor health or limited communicative opportunities can negatively impact on the development of the internal language system. The individual’s response to interaction and situational events, general well-being, emotions and other factors all influence the formation and organisation of symbolic representations. This organisation has implications for efficient retrieval; failure to develop a sufficiently detailed and well-organised representational system may lead to difficulties or inefficient retrieval, i.e., language problems (Nash & Donaldson, 2005). The link with visual images A very close link exists between the symbolic representation and the visual/image representation for that concept. A longstanding debate about whether image and verbal representations are separate, parallel or the one underlying system, has been discussed in an enormous body of literature which was beyond us to fully cover (e.g., Ley, 1983; Paivio, 1971). We considered the researchers’ very definition of language would influence their research methodology, and that findings might depend upon how it was investigated. Findings from positron emission topography (PET) investigations suggest that largely the same parts of the brain are activated for pictures and for words (Vandenberghe, Price, Wise, Josephs & Frackowiak, 1996). Clark (2006) also suggested that it is plausible that the internal language system plays a mediating role in image storage and access. Rather than trip on this early point, we decided simply to assume that the visual image and symbolic representation are very closely linked. Links to cognition We could find no widely used definition of cognition , even in psychologists’ reviews of the literature (P. Clayton, personal communication, 20 August 2006), so we used the term cognitive capacities for simple mental processes, and thinking for higher level, integrated mental process. Cognitive capacities, such as memory and attention, are necessary for the formation and organisation of symbols (Flavell, Miller and Miller, 1993). In our model these cognitive capacities are conceived of as a capacity of the brain structure, rather than as entities. These capacities are drawn upon for forming, organising and accessing the internal language

system. The exercising of a cognitive capacity, such as memory, supports its further development, and this develop­ ment in turn allows more sophisticated organisation of language – a sort of mutually expanding capacity and complexity in language organisation. This is represented in the model by an arrow spiralling outward through cognitive capacities and the internal language system shown in figure 3. The application of a cognitive capacity to the formation or access of symbolic representations is the only way this capacity can be observed, i.e. a child can only “attend” when “attending to something ”. Thus, while cognitive capacities are conceptually distinct from language, they are functionally interwoven, and impossible to separate out in real-life situations. This is important for practice in that many sup­ posedly language-free measures of cognitive functioning are directly or indirectly dependent on language (Camarata & Nelson, 2002). In our model, language is heavily dependent upon the cognitive capacities, but is itself a discrete construct.

Cognitive capacities

Internal language system

Figure 3. An increasing spiral of cognitive capacity and internal language complexity Links to spoken and written codes The internal language system is not observed directly; it is neurologically situated and manifest only through spoken, written and other codes. Spoken language symbols and written language symbols are the material manifestations of the same underlying language system in the brain (Clark, 2006). The written word is not a symbol for the spoken word. They are both symbols for the one underlying concept (although there is a relationship between the “form” of words in the spoken and written codes). Other codes for com­ municating, such as signs and pictorial symbols, are also the material manifestation of the same underlying language system. All forms of communicating and thinking use the same internal language system as illustrated in figure 4. For example, mathematic symbols are types of material symbolic representations for concepts that are stored and organised within the same internal language system as words (Clark, 2006). An individual’s experience of these material (i.e., manifest in the world) symbols and codes influences develop­ ment, represented by the feedback arrow on the model. This part of the model represents a specific challenge to common representations of language by speech pathologists. Typically, written language is considered as having material form (it can be seen on the page), whereas spoken language is equated with the internal language (and considered “immaterial”). However, both spoken and written symbols can be measured and should be considered as “material”. Much of the literature outside speech pathology that we sourced stressed the importance of distinguishing between the internal language system and its material manifestation in the world: the actual spoken and written symbols themselves (e.g., Clark, 2006).

ACQ uiring knowledge in sp eech , language and hearing , Volume 11, Number 1 2009

19