The apple example seems off, but literacy is still going to be a requirement for this kind of thing to work. First, you need to be able to understand the language(grammar, vocabulary etc) to communicate with this device. The guy in the demo is literally thinking in English, Mandarin. I'd actually argue that only highly literate people will be able to use this device really well. This device is not reading thoughts, it's inferring the silently spoken words.

You're still confusing literacy with fluency. Literacy is not going to be a requirement, because the technology doesn't require reading or writing, and being literate is literally defined as being able to read and write.