Ingrid K. Christoffels

Speakers use external auditory feedback to monitor their own speech. Feedback distortion has been found to increase activity in the superior temporal areas. Using fMRI, the present study investigates the neural correlates of processing verbal feedback without distortion. In a blocked design, the following conditions were presented: (1) overt picture‐naming, (2) overt picture‐naming while pink noise was presented to mask external feedback, (3) covert picture‐naming, (4) listening to the picture names (previously recorded from participants' own voices), and (5) listening to pink noise. The results show that auditory feedback processing involves a network of different areas related to general performance monitoring and speech‐motor control. These include the cingulate cortex and the bilateral insula, supplementary motor area, bilateral motor areas, cerebellum, thalamus and basal ganglia. Our findings suggest that the anterior cingulate cortex, which is often implicated in error‐processing and conflict‐monitoring, is also engaged in ongoing speech monitoring. Furthermore, in the superior temporal gyrus, we found a reduced response to speaking under normal feedback conditions. This finding is interpreted in the framework of a forward model according to which, during speech production, the sensory consequence of the speech‐motor act is predicted to attenuate the sensitivity of the auditory cortex. Hum Brain Mapp 2007.

Simultaneous interpreting is a complex task where the interpreter is routinely involved in comprehending, translating and producing language at the same time. This study assessed two components that are likely to be major sources of complexity in SI: The simultaneity of comprehension and production, and transformation of the input. Furthermore, within the transformation component, we tried to separate reformulation from language-switching. We compared repeating sentences (shadowing), reformulating sentences in the same language (paraphrasing), and translating sentences (interpreting) of auditorily presented sentences, in a simultaneous and a delayed condition. Output performance and ear–voice span suggest that both the simultaneity of comprehension and production and the transformation component affect performance but that especially the combination of these components results in a marked drop in performance. General lower recall following a simultaneous condition than after a delayed condition suggests that articulation of speech may interfere with memory in SI.

Simultaneous interpreting (SI) is a complex skill, where language comprehension and production take place at the same time in two different languages. In this study we identified some of the basic cognitive skills involved in SI, focusing on the roles of memory and lexical retrieval. We administered a reading span task in two languages and a verbal digit span task in the native language to assess memory capacity, and a picture naming and a word translation task to tap the retrieval time of lexical items in two languages, and we related performance on these four tasks to interpreting skill in untrained bilinguals. The results showed that word translation and picture naming latencies correlate with interpreting performance. Also digit span and reading span were associated with SI performance, only less strongly so. A graphical models analysis indicated that specifically word translation efficiency and working memory form independent subskills of SI performance in untrained bilinguals.