Neologism production in jargon aphasia

This study investigates a jargon speaker, LT, whose connected speech is composed almost entirely of neologisms. Despite the general intelligibility of his speech, LT is able to produce discrete responses in picture naming tasks. Neologisms were investigated for their phonemic content. Non word responses maintained the normal English distribution of phonemes. Importantly, they also showed greater than chance levels of target relatedness. Analysis of LT's responses to a set of stimuli controlled for their consonant content allowed more detailed investigation of the nature of target and error phonology. A strong influence of phoneme frequency was identified. Higher frequency consonants showed a pattern of frequent but rather indiscriminate use. They often appeared in target related contexts but were also frequently misused in contexts where they were not required by the target phonology. Lower frequency consonants were realised less often. However, their use was restricted to target related contexts and they seldom appeared as error phonology. Further investigation showed that LT's ability to realise target phonology was influenced by the nature of the output task. A semantically primed reading condition resulted in a significant increase in the number of correct responses. Neologistic output showed a significant increase in the ability to realise target phonemes. Patterns of individual consonant use also showed significant changes. High frequency consonants showed a more refined distribution, appearing less frequently as error phonology. Low frequency consonants increased their rate of use but continued to be restricted to target related contexts. The findings of the investigations are discussed. The results are best explained by theories of neologism production which maintain a direct relationship between target and neologistic phonology and which propose a single mechanism underlying the production of both target related and abstruse neologistic output. Interactive activation accounts of lexical processing appear to be well placed to explain LT's output and a preliminary account is offered. Recommendations for the future investigation of neologistic output are made