I think the problem is more, will there be enough people to
make up an audience? Most of the people there will be German,
and it's tiring listening to talks not in your first
language... Or do you think it will be possible to get a
non-german audience in Berlin? ;-)
There are, of course, also Germans who can understand English
without problems, however these are mostly technically
interested, young people, or people with internet access. OTOH,
there are lots of people who have never had any English in
school (e.g. in Eastern Germany, it was facultative), and there
are people who have not practiced any English for years. (There
is an enormous cultural isoolation here, as almost all films and
TV shows are dubbed (except for Mr.Bean and Monty Pythons Flying
Circus, which are subtitled ;o) ), also there are hardly any
English cinemas or TV channels (except for CNN and MSNBC, which
both suck :o( )).
So, I expect there will be an audience for English spoken talks
(IIRC, the room in which your Free Harware talk took place was
filled up quite well), but the people going there will be
preselected a bit. :o(