With my dad in particular, if the icons were literally photos (as opposed to "graphically designed" icons) of real world objects he was familiar with, I think it would help... a little.

He doesn't seem to process abstractions very well. For example, a shadowed head in a contacts icon has absolutely zero meaning for him.

Even with non-touchscreen UI's, such as a media player, my dad doesn't quite grasp the concept of a highlighted item no matter how many times I try to explain it to him. It gets even more confusing for him if the highlight changes color in different parts of the UI.

It would be nice if voice ui's were more advanced, but he speaks a dialect of Chinese that's much less common than Mandarin or Cantonese, so there's another issue.