The Witcher - Enhanced Edition Interview @ RPS

CD Projekt Red's Michal Madej has spoken with Rock, Paper, Shotgun about The Witcher and the upcoming Enhanced Edition.  Here's the definitive answer about the translation in the original release, which is improved in the new version:

What caused the significant, let’s say “differences”, between the Polish and English dialogue in the original game?

It was hard lesson to be learned for us – the localization process. At beginning of the development we had to make production estimates for the amount of English text to be recorded, and we based it on our experiences with Polish localizations. The assumption we made was that, as Polish text after translation from English is usually about 20% longer, the reverse translation would be shorter by a similar amount. We just didn’t realize that we were using different measures – number of pages and number of words. Because of how the English language works out, the resulting translation was way too much for recording, which came into play at the very last stage of development. We had a really short time to edit all of the English dialogues, shortening them by 30%. So basically, the original translation was really good; it was just trimmed due to production.