Star Wars: Knights of the Old Republic/Zaalbar

Zaalbar joins your party when you and Mission rescue him from the Gamorrean compound in the lower sewers on Taris.

You can't really unlock further dialog by speaking to him, but when you travel to the Wookiee home world Kashyyyk his backstory is revealed, and you can meet his brother Chuundar and father Freyyr.

However, after first entering Rwookrrorro village he's removed from your party until you complete the Chieftain in Need quest, which isn't necessary to get the Star Map on Kashyyyk: this means it's possible for Zaalbar to remain on Kashyyyk for the rest of the game, either by accident or design.

Banter

Mission may speak to Zaalbar when both are in your party:

Mission: Hey, Big Z, we've got to do something about your breath. I didn't want to say anything, but it's bad. Worse than usual, which is hard to believe. In fact, now that I think about it, your breath has been pretty rancid ever since we rescued you from those Gamorrean slavers. What did they feed you, buddy?

Zaalbar: They didn't. I wasn't their guest, Mission. I was a prisoner. I don't think they cared much what happened to me.

Mission: Oh, Zaalbar, that's terrible! I know how grouchy you get if you don't get your eight square meals a day. I'm amazed you didn't pass out from hunger.

Zaalbar: I did manage to take a chunk out of the arm of a guard that wandered too close to my cage. But it tasted awful, so I spit it out.

Mission: Ewww! No wonder your breath is so bad, Big Z. Gamorreans smell like bantha poo-doo! We'll have to pick you up a toothbrush to clean that stench out of your choppers.

Zaalbar: Wookiees do not brush their teeth, Mission! It… it just isn't done! What humiliation will you use on me next? A comb?

Mission: Okay, relax. No toothbrush. Sheesh. Just try to eat something else to cover up that smell, okay? Stay away from anything that's smart enough to lock you in a cage this time.

Zaalbar: *Sigh* I'll take care of it as soon as I can, Mission. For now, let's stay focused on the task at hand.

Afterward, she may speak to him again:

Mission: Hey, Big Z. Don't take this the wrong way, but lately I've noticed you're starting to look a little bit scruffy.

Zaalbar: Scruffy? What are you talking about? I hope you aren't suggesting I take a bath!

Mission: No, I'm not suggesting a bath. I know how well that went over last time. But your hair's getting all tangled. And if you look close, you can see a few gray strands starting to poke through.

Zaalbar: You're making this up! I groom every day! My hair is not tangled, and it's not going gray!

1. She's got a point, Zaalbar. You could use a good makeover.	2. Zaalbar looks fine to me.
Mission: Don't worry, Big Z. It's nothing I can't fix. A little trim, a splash of coloring and you'll be as good as new. Best-looking Wookiee on the planet. Maybe a nice suit…
Zaalbar: You don't trim a Wookiee! You don't color a Wookiee! And you certainly don't dress a Wookiee!
Mission: I know Wookiees aren't into the whole clothing thing, but you could start a whole new trend! You'd be on the cutting edge.
Zaalbar: Rargh! Leave me alone!
Mission: Okay, okay. Sheesh. Try to offer some constructive criticism and this is the thanks I get? Let's move on. You can just stay naked and scruffy for all I care.

Commentary

Even if you don't speak to Zaalbar directly he may comment during dialog when in your party, although unlocking this may also be conditional on others being added or removed, among other things:

Taris

Location	Dialog	Add	Remove
Javyar's Cantina	Zaalbar
Upper City North	Ithorian	Mission
	Gorton Colu

Dantooine

Location	Dialog	Add	Remove
Courtyard	Elise
Jedi Enclave	Juhani
	Crattis Yurkal		Carth

Tatooine

Location	Dialog	Add	Remove
Anchorhead	Sharina Fizark		Juhani, Bastila, Jolee, Carth, Mission
	Sandcrawler Mechanic
	Iziz		Bastila
Hunting Lodge	Tanis Venn (female)		Jolee, Carth
Swoop Registration	Motta the Hutt
	Nico Senvi		Bastila, Jolee
Cantina	Czerka officer
	Jawa Servers
Eastern Dune Sea	Komad Fortuna		Mission, Juhani
	Star Map		HK-47

Kashyyyk

Location	Dialog	Add	Remove
Czerka Landing Port	Komad
	Zaalbar
	Czerka Scientist
	Janos Wertka
	Czerka Guard Captain
Great Walkway	Zaalbar
	Captain Dehno or
	Wookiee Guard
	Wookiee Guard
Hall of the Chieftain	Chuundar	Mission
	Freyyr
Great Walkway	Rwookrrorro Guard
Village of Rwookrrorro	Wookiee
Woorwill's Home	Jaarak
Worrroznor's Home	Worrroznor
Czerka Landing Port	Janos Wertka
	Eli Gand
Lower Shadowlands	Grrrawahrr
	Ritual Speaker
	Mandalorian Commander
	Computer

Manaan

Location	Dialog	Add	Remove
Ahto West	Shaelas

Korriban

Location	Dialog	Add	Remove
Dreshdae	Port Authority	Mission
	Lashowe
	Czerka Representative
Sith Academy Entrance	Mekel
	Prospective Sith		Carth, Juhani, HK-47
	Sith Academy Guard		Carth
Sith Academy	Uthar Wynn
	Kel Algwinn
	Tariga
	Lashowe		Jolee

Ebon Hawk

Location	Dialog	Add	Remove
Main Hold	Strange Stowaway	Mission

Leviathan

Location	Dialog	Add	Remove
Ebon Hawk	Captured by the Leviathan
Ebon Hawk	Escaped the Leviathan

Star Forge System

Location	Dialog	Add	Remove
Ebon Hawk	Mission
	Trouble With Gizka
North Beach	Rakatan Elite Warrior		All but T3-M4
Central Beach	Carth (romanced)

Star Forge

Location	Dialog	Add	Remove
Deck 1	Zaalbar

Party

Location	Dialog	Add	Remove
Any but Ebon Hawk	Mission	Mission