Margaret Peregrine is a high school sophomore. Most of the time, she's either at school, at the school robotics club, at the school chess club, or doing schoolwork. Today, she's cleaning out her late great-grandmother's attic.
"Not a problem! I appreciate you taking the time for this. Ready to hear the first tape?" Provided he says yes, she sets the first of the seven recordings going, pencil and paper at the ready to note down anything he can figure out.
"I'm afraid I don't know--it's not my great-grandmother's voice, or anybody's I recognize."
"That's odd." (She's not actually surprised.) "Can you tell me what the words you did recognize mean?" She might be able to infer the rest from context and her background knowledge, and if not she can potentially fill in the gaps with her own incantation design skills.
"Maybe Great-grandma was a secret Wiccan. Or a secret Dungeons and Dragons player."
"I don't know anything about Wicca, but in Dungeons and Dragons you can cast your pretend spells in whatever language you want. Can you translate as much of it as you understand? You've gotten me really curious."
"Yeah, I can do that, either by mail or just dropping them off at your office. Do you want the player too?"
It's a risk, but probably not a big one. He would have to do something weird with the playback, notice the odd behavior, and not write it off as old technology misbehaving.
"Cassette tapes, pretty old ones." She reads the brand off the side of one of them.
"Sure thing. It's not the most reliable machine, but it can get sound out of the tapes." And now he has a convenient wrong hypothesis on hand if he tries to fast-forward or something. "Can I bring it all to an office somewhere? I'm worried something would get damaged in the mail."
Once she's off the phone, Margaret does a quick test of the fast-forward function. She fully expects it to do something incorrect, but isn't sure what.
That's what she had expected, but looking at it it's even more obviously wrong than she had imagined. She paints the inside of the clear window black to make it slightly less obvious and adds a post-it note saying "Don't use the fast-forward, it's broken!" And while she's at it, she verifies that rewinding the tape is silent as she intended.
Good. Satisfied that the tapes are less implausible than magic, she boxes them and the player up, labels the whole thing with her name and phone number, and drops it off at the professor's office the next time it's a weekend. Then it's back to researching experiment design and thinking about the preliminaries of a spell for identifying what kind of critter someone is.
As long as he's just busy and not, say, investigating the Case of the Impossible Tapes, that's fine by her. She has plenty of research-about-research to do, and a diagram to draw, specifically one for visual illusions using the "light" and "control" runes. The best way to implement the critter-detecting spell is probably to show people holograms of their true forms, both in terms of what the magic will understand and in terms of what potential critters will find useful, and the first step towards that is complex visual illusions.
This one is big from the start; she's going to be leaning on the magic for a lot of the data handling. Once it's done and checked, she puts a paperweight on it and recites her translation of, "A foot above this diagram, create a visual illusion of the object touching the diagram, to scale."