The player characters only ever say one line, and they say it to everyone they meet.
Subverted: After you talk to one NPC a certain number of times, he says something different.
Double Subverted: He then proceeds to say that every time you speak to him.
Parodied: The Idiot Hero tries to hold a conversation with an NPC who can only say one thing.
Bob: "Excuse me Ms. Jones, did you see my friend Alice? I swear, she just ran off this way!" NPC: "Hello, welcome to Everytown. My name is Olivia Lloyd, what's yours?" Bob: "I already told you, my name's Bob Johnson! Did you happen to see Alice walk by?" NPC: "Hello, welcome to Everytown. My name is Olivia Lloyd, what's yours?"
Zig Zagged: Some NPCs have limited dialogue, some are more interactive.
Averted: The only NPCs in the game are the ones involved in cutscenes; the player never gets to talk to them directly.
Enforced: "Most players will only talk to these guys once, so why waste money paying the writer to come up with additional dialogue?"
Lampshaded: "So why is it that we're able to say so much more than most people are? It's almost like we're the only intelligent people left on Earth!"
Invoked: Most of the NPCs are at least somewhat interactive, but one lost a bet and has to say the same thing every time someone talks to him.
Exploited: The Big Bad kidnaps one of the characters right in front of several townsfolk, and then captures the rest, because the NPCs can't warn the player.