Now some of these guys weren't amazing presenters in German either, but my point is that they should not have to be. Some people simply are dry explainers and they don't naturally entertain. Nothing wrong with that at all, especially with such nerdy topics. But in those cases, I'd much prefer a lengthy blog article, or maybe a podcast interview with a capable host. Please, CCC, don't send these people on a stage that they don't enjoy when you could also work with them to get their stuff across.
And with how much is consumed as VOD, I don't think the live talk brings a lot to the table anymore. There could be live Q&A sessions for those who read article or heard the podcast interview.
(I'd argue the same for an academic context by the way - anything above seminar size is either a celebration or a sermon, but not a discussion.)
My best experience at CCC was to literally stumble over bunnie on the side of a hallway where he was sitting against the wall, introducing his own ARM laptop to a dozen of people or two.
And don't tell me this doesn't scale - he has also gotten his message across in ways that scale. But there was finally a natural way of asking questions in a back and forth manner that wasn't in front of a 500 people audience.
The speakers are not selected by the CCC; they have to apply with a synopsis of their talk.
Perhaps you could do us all the service of making a blog post for each of the CCC talks this year? :D
Hmm, maybe this is actually a problem the community can address. For our conferences, people who are new to giving talks normally have a practice run or two at their universities with local people. Then they get feedback how to improve the talk. It doesn't work wonders, but it does help quite a bit. Not only does the feedback help improve the slides, the style of presentation, it also builds confidence.
Maybe CCC/somebody could organize optional "training sessions" where people can give test-runs. I'd volunteer to listen and give feedback. Or maybe a tutorial: "How to give a good congress talk"
I'm all for giving a presentation in the language you're best at. Let machine translation (or manual translation) pick up the slack, not one person's possibly-mediocre ESL skills.
I also can speak German but I avoid doing so when technical accuracy is paramount, because sometimes, small details really matter.