This is sort-of dipping into Writing territory as opposed to Character territory, but the other thing that you could try is making a character's actions talk, as opposed to the character themselves.
Sure, if your character is just going to shut someone down verbally then they'll run out of things to mention and quickly leave. But if you give them bits and pieces of things to go on through things that might not necessarily be verbal, then there are ways of carrying the conversation on, provided that your character is willing to at least talk a little bit. Maybe give them glimpses at that book your character is reading, or have them fiddle with some odd trinket on their person. Even if a character doesn't talk, you can hold a player's interest by giving them things to talk about.
Sure, if your character is just going to shut someone down verbally then they'll run out of things to mention and quickly leave. But if you give them bits and pieces of things to go on through things that might not necessarily be verbal, then there are ways of carrying the conversation on, provided that your character is willing to at least talk a little bit. Maybe give them glimpses at that book your character is reading, or have them fiddle with some odd trinket on their person. Even if a character doesn't talk, you can hold a player's interest by giving them things to talk about.
