Hi, in Zurich you can join the theater group ZCC http://www.zcc.ch/
I don't know how they work.
In Berne a group of the Upstage players www.upstage.ch
has formed an
improvisational theater group, see www.areyouserious.ch
. They are
next at the www.englishclub.ch
on June 13.
Try toastmasters, www.toastmasters.ch
, it is a lot of fun.
Every meeting requires members to give impromptu presentations
on given topics. And great speeches are often more afting than speaking!
There are clubs in many Swiss cities and you can attend a few times
to see if it is for you .