Existing simultaneous interpretation process models lack an account of intermediate representation compatible with the cognitive and linguistic processes inferred from corpus descriptions or psycholinguistic experimentation. Comparison of SL and TL at critical points in synchronised transcripts of German-English and Chinese-English SI shows how interpreters use procedural and intentional clues in the input to overcome typological asymmetries and build a dynamic conceptual and intentional mental model which supports fine-grained incremental comprehension. An Executive, responsible for overall coordination and secondary pragmatic processing, compensates at the production stage for the inevitable semantic approximations and re-injects pragmatic guidance in the target language. The methodological and cognitive assumptions for the study are provided by relevance theory and a ‘weakly interactive’ parsing model adapted to simultaneous interpretation.