Monitoring via the perceptual loop: is the inner loop based on perception or production?

To monitor one's speech means to check the speech plan for errors, both before and after talking. There are several theories as to how this process works. We give a short overview on the most influential theories only to focus on the most widely received one, the Perceptual Loop Theory of monitoring by Levelt (1983). One of the underlying assumptions of this theory is the existence of an Inner Loop, a monitoring device that checks for errors before speech is articulated. This paper collects evidence for the existence of such an internal monitoring device and questions how it might work. Levelt's theory argues that internal monitoring works by means of perception, but there are other empirical findings that allow for the assumption that an Inner Loop could also use our speech production devices. Based on data from both experimental and aphasiological papers we develop a model based on Levelt (1983) which shows that internal monitoring might in fact make use of both perception and production means