In the bottom right corner of the player is a button labeled "native" it opens a dropdown in which you can select translation

I too could not find them on media.ccc.de, but this is the list of English talks from 35C3 https://www.youtube.com/playlist?list=PL_IxoDz1Nq2YUlQqBSg0F...

This has both English-spoken and translated videos on it.

It's available, but a bit hidden on media.ccc.de. There's a cog wheel icon on the lower right corner of the video player. Hover over it, and a list of languages ("deu" is German, "eng" is English, "fra" and "esp" are French and Spanish, respectively) should pop up.