Orca Speech not interupting as expected

[bart bunting net au]

Hi all,

I'm new to orca and have it working, both on my debian sid and ubuntu
edgy installs.  I'm using dectalk for the speech but the problem I'm
about to describe happens also if I use festival.

On one machine (the ubuntu one) the speech does not interupt as I
would expect.  For example if I arrow around on the desktop orca reads
every icon in sequence that i move over without any interupts to
speech even if i arrow quickly.  

If i do the same thing on the other machine it exhibits the expected
behaviour, interupting speech when I hit the arrow key and immediately
starts speaking the name of the new item.

Is this a setting somewhere or something, it's really anoying to have
to listen to all that extra speech :).

Cheers

Bart