The main topic of this paper is the importance of certain acoustic condtions affecting the interpreter’s performance and also the effect of the feedback of the interpreter’s voice into the ear. The paper aims to show the preliminary results of an experimental study on the effects of delayed auditory feedback (DAF) during simultaneous interpretation. Critical DAF values in students of simultaneous interpretation were first of all assessed during verbal tasks other than simultaneous interpretation. The authors could not assume by default that simultaneous interpreters would show the same disruption effects as normal speakers.