I used my mine in the same way with the PSR9000 (when I had one). Years ago Cascio made a little small keyboard that had a sampler. It had mini-keys and ran off batteries. Radio Shack sold it for around $200. I still have two of them. There is only room for a couple of phrases, but it works amazingly well. It was lots of fun to play with.
I used to say things like "more beer", or "why don't you take a break", and then play it back on several different keys, with pitch change.
DonM