Opportunity cost and the digital recorder

I am pondering the usefulness of a digital voice recorder. I've actually pondered it for a long time. I do a lot of reading out loud to my kids and have thought that it would be nice to record some of that. I've also thought of the usefulness of letting kids record their spelling lists as practice. Kiki could use it to record her Japanese vocabulary words. And the biggest motivator of all is that Link needs practice reading aloud. I could have him read to the recorder so that his...