In order to produce a validated software product the output of requirements elicitation studies will have to be translated into a precise specification that can be implemented in technologies that today are likely to be object-oriented and component based. In order to provide a structured approach to development which maximised the opportunities offered by new software technologies we needed a framework which provided an effective bridge between requirements elicitation studies and software design and implementation. In the PCAD Project we have conducted interviews with end-users, communication partners and speech and language therapists. Typical communicative situations have been observed in order to identify natural communicative strategies that people with dysphasia use. The state of the art of AAC and dysphasia has been reviewed.
Software engineers require highly focussed results for translation into effective specifications.
Developing with Users Variation in dysphasic end-users' language and cognitive competencies together with the inherent complexity of the language disorder mitigate against the use of a linear software development model often referred to as the waterfall model. An important feature of the approach used in PCAD is that products should be developed with users in an iterative manner. This is illustrated in Fig1 and employs the mainstream software engineering practice of iterative development with incremental delivery. An increment is a self-contained block of functionality that is useable as a stand alone deliverable. Code increments are evaluated with users and the results fed back to modify the design.