... Or more likely Jens thinks that his spoken English really sucks and didn't want to say one more word. It's not so easy to start talking a language that is not yours and for some people it takes a lot to overcome the fear of being ridiculous. It's a whole psychological stuff... You wouldn't believe how it was for me the first time I was confronted to people for whom English was the native language.
Well, no in fact it was the second time

The first one it was in Brighton (UK -- in '86 or '87, can't remember exactly) with a nice lady who had a shop on the beach front and seeing that I was French she wanted absolutely to speak French -- just to be nice, you see. So I appreciated the gesture a lot but I wasn't able to push a single English word in the whole conversation...
The second time was better because the people I met didn't want to bother about speaking French one bit. And for some reason (that I understood later) they found my first sentence pretty amusing. Well at least being a laughing stock for a bit didn't prevent me to learn English further... I guess that if I feared to be ridiculous, I wouldn't even be there

As for Thomas, yeah, considering that he's the programmer, he actually got most of the stuff working in Penumbra, had to care about the engine and the graphics... that's a whole lot of stuff so he certainly has the most to say about it no matter what.