What I mean by that is that a translator reads and writes whereas an interpreter listens and speaks. So, a translator will receive a document, read it through and type up a translation It's very good if you need a precise translation, perhaps a legal contract every word must be correct but it takes a long time.
What an interpreter does is immediately tell you what the other person is saying. That means of course it's very for meetings, conferences where you don't want to wait three days to read a translation. It does mean though that the interpreter can never be quite as precise as a translator and in fact that's part of the fun of interpreting It's very creative.
You often find that you have to reconstruct what the speaker is saying, you don't go through it word by word, you might find yourself telling their story or making their argument in a completely different way, using different sentences and different words to make the same point. You might also sometimes find yourself adding some cultural information. The speaker might say something which everyone understands in their culture but for your listeners to understand, you might quickly have to add a couple of cultural points. Basically, there are two main kinds of interpretation: consecutive and simultaneous. Simultaneous interpretation is what you can see people doing here in the rooms behind me. While I am speaking they are immediately interpreting my ideas so that someone else can listen to straight away. It's very good for a meeting or a conference. Consecutive is what you do if you haven't got all this technology, you're perhaps walking around a farm or you're perhaps meeting in a small room somewhere.