Students can sometimes make good interpreters. A student may be a specialist in the subject area and already know all the terminology (in both target and source language). However, as the person has not been professionally trained and has limited experience what happens if they dont understand - do they seek clarification or simply leave bits out or even insert their own ideas - after all, they dont want to admit they werent listening or didnt understand.
 

Another area where errors are frequently seen through the use of untrained interpreters is in the handling of questions. Questions are asked of the presenter which the student interpreter answers - "after all - this is my subject area too" - leaving the presenter out of the loop. The presenter misses out on feedback and can never be sure that his/her message has been conveyed completely.
 

Another telling example of inappropriate interpreting is where relatives (even children) are used as interpreters, for example in the health sector, when a health professional is discussing an illness with a patient. Think about the impact on the family and the child, say, if the child has to explain bad news.