“The illuminating quiet”: a metaphor analysis of autobiographical descriptions of inner speech in aphasia

Background: Inner speech in aphasia is a rapidly expanding research area, but can be defined in numerous ways. Unlike behaviourally observable language processes such as overt word-production, inner speech is only directly available to introspection. Subjective experience thus grounds our understanding of inner speech and is a necessary starting point for investigating its definition. Descriptions of inner speech written by people with aphasia can make an important contribution to conceptual clarity in the literature. This important data source has not been systematically analysed. Our research addresses this gap. Aims: This research aims to understand the subjective experience of impaired and preserved inner speech in aphasia, through analysis of the metaphors used in autobiographical acco-unts, and to interpret the findings in relation to the inner speech literature. Methods & Procedures: This study carries out a metaphor-led discourse analysis of descriptions of inner speech in four autobiographical accounts of aphasia. Metaphorical expressions describing language processing were identified and coded, then systematic metaphors (i.e., the related concepts which are used consistently to describe a particular topic) were described. The metaphors used to describe inner speech were then analysed, with attention to patterns of use and contextual information. Results & Discussion: 338 expressions made use of the main systematic metaphors which were used to describe inner speech. Two types of inner speech- Phonological Inner Speech and Dialogic Inner Speech - were described as distinct and dissociable experiences, and were described using different metaphors. Phonological Inner Speech, the internal activation of phonological representations, as used in mental repetition of a word or phrase, was described by two authors using the metaphors WORDS AS OBJECTS, MIND AS CONTAINER and INNER SPEECH AS HEARING WORDS. Dialogic Inner Speech, the use or awareness of linguistic inner reasoning or dialogue, was described by two different authors using the metaphors INNER SPEECH AS INNER VOICES/PERSONS/MONOLOGUE/DIALOGUE and APHASIA AS SILENCE/ FLUID/ SPIRITUAL EXPERIENCE. A double dissociation of these different definitions of inner speech is seen across two of the accounts. Different impacts on language processing and cognition were also described. Conclusions: This research demonstrates that subjective accounts of inner speech can help clarify theoretical discussions and clinical implications. Although, recent research within aphasiology has focused mainly on Phonological Inner Speech, we show that in these accounts the impairment of Dialogic Inner Speech was described as more salient and more explicitly as a ‘lack of inner voices’.