Relative clause sentence production using augmentative and alternative communisation systems

Complex syntactic structures may be difficult to recognize when produced us ing augmentative and alternative communication (AAC) systems that do not co ntain grammatical markers. The present study investigated adult English spe akers' production of Subject and Object relative clause sentences using a p icture/symbol-based AAC system with speech output. Most participants avoide d the potential ambiguity that resulted from the absence of grammatical mar kers. They followed spoken English word order when encoding Object relative clause sentences, but altered this order for Subject relative clause sente nces. Most participants used constituent proximity to maintain the distinct ion between Subject and Object relative clause sentences. Results indicate the combined effects of underlying syntactic knowledge and pragmatic Variab les on the AAC constituent order patterns observed.