It's the voice detection. There's certain villagers I have to say their names differently than I normally would just to get it to register with the megaphone. I had the hardest time when I had Ken. It was rare when I got it to work for him.
I always tend to get Kapp'n to respond even if the name doesn't sound remotely like it. I have to say their name with almost no expression for them to respond.
Kapp'n seems to think he's Katie sometimes for me... Also, Saharah and Cyrano mix up pretty often when the former's in town and I'm trying to track her down.
When I called for Frank, Kapp'n kept responding. I ended up finding Frank - who was hiding behind a house only a few steps from where I was.... in the north part of town!
I remember when I had Phoebe and she would never answer. It didn't matter how I pronounced her name and I tried every pronounciation I could think of: Fee-bee, Foe-bee, Foe-eb-bee, Po-bee... LOL
How weird...
Kapp'n always responds for me too. But I know where he is!.. It's not like he goes anywhere. A few times I called for Lucky and Kapp'n responded. Pff.
Kapp'n responds a lot in my old town, where I have Katt. It's hellish.
Purrl also responds a lot. She responded to me calling Eunice once, who for some reason only responds when I say it like 'You-niece'.
Kapp'n answers most of the time. Isabelle, Redd, Badge Guy, and Joan answer when you call different villagers names.
One afternoon I spent time saying things and Isabelle answered back. She answered back to Witch.
I've had Kapp'n reply, but never Isabelle, Redd, or Phineas! I want to try it though (one day when my parents aren't home and I'm hiding in my bedroom)