[Ack, do radios not exist wherever she's from? Well it must be time for Professor Kevin to explain!] It's this thing that lets you listen to other people singing. So if you sang into the journal, it'd be like a radio 'cause other people could open their journals and listen to you.

(Disney likes to squeeze every last drop out of their available repertoire of stars. :Ia And I am more than happy to implant such delicious ridiculousness in your mind. 8D I'd link to videos for mental image enhancement, but quite honestly no one needs to see the horror that is Kevin-plus-hair-straightener.)