“Without prejudice” means without prejudice to the progress or outcome of any claim or potential claim between the parties. Words of this kind are to be understood after “without prejudice” and are not expressed, which is why it is not easy to translate into another language. It is a peculiarly English legal maxim. If the right conditions are met, a court will recognize that certain negotiations, tape recordings, documents, etc. are inadmissible as evidence.
Sometimes people use the maxim on correspondence without really understanding what it means and irrelevantly or inappropriately. Sometimes they just mean “confidential”!
The without prejudice maxim came into being to enable the parties to attempt to settle a matter out of court or without going to trial. It is meant to encourage parties to express themselves freely and without inhibition. A claims xyz against B. If B approaches A to ask if they can compromise, then it could be interpreted as an admission of liability by B. Therefore B will not do this unless there is some safe space or container in which he can do so to test how willing A is to compromise.
Simplistically expressed, the idea of without prejudice negotiations is that B can, using the umbrella of “without prejudice” negotiations, approach A. Negotiations must be genuinely aimed at settlement, that is, the avoidance of litigation and if this criterion is met, the proposals put forward or the arguments in support are not able to be brought up in evidence later on. For example one party may ask the other for more time, or a reduction in what he has to pay.
If this is going to be translated into German, then I think that it would be good if something along the lines of my first sentence were conveyed. The one I like best is from the dictionary definitions above is: “ - (Jur) ohne Beeinträchtigung /or/ unbeschadet irgendwelcher Ansprüche” from Pons-Collins.
Apologies if this is a bit long-winded.