"Define text" is a pretty good question, but "ASCII" v. "Unicode" is frankly one of those deeply nerdy things that won't matter much at all in the grand scheme of all of this.

I suspect those familiar with pre-computer languages/linguistics would be able to come up with a pretty good working definition here, but something like "communication systems that utilize a relatively small number of repeating symbols to convey meaning, often associated with vocalizations?"