There is now a RISC OS Squeak 4.0 with actual sound output available for testing - try http://www.rowledge.org/tim/squeak/Squeak3-9c-RISCOS.zip to download a bundle of the entire squeak setup, including the DeepKeys and SharedSoundBuffer modules, the Squeak .source file already installed and the image/changes file ready to go.
And if that seems to work, you might try a very sketchy Scratch try-out by downloading http://www.rowledge.org/tim/squeak/Scratch-RISCOS.zip – but you’ll need to have grabbed theSqueak package first in order to have the deepkeys/ssb modules.
tim -- tim Rowledge; tim@rowledge.org; http://www.rowledge.org/tim There are two ways to write error-free programs; only the third one works.