I would echo AVCP in that, 'turbulence' is usually interpreted as 'being thrown all over the sky'! Before departure: "We might feel some small bumps as we go up through this cloud - but it's all clear above." and this can be reversed prior to let down. If it is likely to be medium turbulence then, "We will go through some bumpy clound on our way to the clear air above them" and so forth.
If you encounter the choppiness when crossing form one jet stream to another: "... sorry that I have had to put the seat belt sign on for this bumpiness but we are just going through a place were two streams of wind cross and we should be out the other side before long."