It took a while for them to notice. The opportunity didn't exactly present itself often.

They were at the market, collecting supplies to take back to the Western Air Temple. It was Aang that noticed.

He looked over to see Zuko, hood up, conversing with a merchant. Not exactly unusual, except he was doing it in the merchant's own tongue. Exhibiting uncharacteristic restraint, Aang waited until Zuko had finished his conversation and walked over to him.

He said, "You speak Merchant's Call?"

Aang made a point of saying it in said language. Zuko frowned at the young Avatar. He shrugged.

Zuko replied in Fire Nation Common, "Yeah, so what? Lots of people do."

"Where'd you learn it?"

Zuko looked away. "I was at sea for a while. You pick stuff up."

Sensing that Zuko was growing uncomfortable, which in turn made him uncomfortable, Aang changed the subject. After that though, he started paying a little more attention.

Like when Suki and Toph were having a conversation in Earthen Common and Toph threw a comment at Zuko in that language. Absentmindedly Zuko responded in the manner of an Earth Kingdom native. When Suki questioned him on it, Zuko simply said, "I travelled in the Earth Kingdom for a while. I learnt it here and there."

Or when Chit Sang stubbed his toe and cursed in a language none of them recognised and Zuko reprimanded him for it. That time it was Toph that demanded to know what had been said.

Zuko had responded, "A word that 12-year-old Earthbenders shouldn't hear."

That comment almost got him thrown off of the edge of the Temple and into the valley below.

The most shocking time though, for Aang, was when he'd been demonstrating the language of the Air Nomads; letting the words flow and drift out into the abandoned home of his people. The language made him both sad and happy. The shock came when Zuko of all people answered him in the same tongue, albeit a little halting and with a strange accent.

That time they all questioned him on it. If Aang thought Zuko looked uncomfortable at the market, it was nothing compared to then.

Aang asked, "How'd you know Air Common? Nobody knows it anymore."

Zuko wouldn't meet his gaze. He muttered, "I thought you'd be an Airbender, so I learned."

Sokka frowned. "What does that even mean? You thought he'd be an Airbender?"

He looked up and met Katara's glare. He swallowed and said, "I was looking for—hunting for the Avatar for… a long time. I learned everything I could. It's, well, it's standard tactics. In the Fire Nation."

Aang frowned. "What do you mean?"

Zuko sighed. "'Know your enemy'. If you know your enemy, who he is, what he can do, then you stand a better chance of defeating him."

Aang asked, "How'd you learn? There was no one to teach you."

Zuko shrugged a shoulder, refusing to meet his gaze. "I taught myself. Bought scrolls. A lot of scholars wrote about the Air Nomads, their—your language."

Sokka interjected, "I thought scholars wrote in their own super-complicated language? Every book and scroll I've found is."

"Yeah, I can understand that. A bit. Enough to work my way through."

"Six." That was Toph, who'd been silent up to then.

Zuko frowned over at her. "What?"

"From what Twinkletoes has said, that's six languages you speak. You've been holding out on us, Sparky."

Zuko's frown deepened. "I-I don't know what you mean. Most people speak more than one language. It's not exactly rare."

She replied, "Yeah, but I'm Earth Kingdom Nobility, and I can speak three, four at a push. My dad barely taught me any Merchant's Call; he always figured my husband would handle the business side of things. How about the rest of you?"

Suki chimed in with, "Four, if you count Kyoshian."

Sokka considered it. "Three properly, then maybe another two. Not well, though. Can't get my head around the Scholars' stuff. It's just… wrong, like it's all mixed up."

Toph said, "Sugar Queen?"

She sighed. "Four, tops. My Merchant's Call is barely there though. And I'm still trying to get my head around Earthen. It's very… dry."

Toph nodded in acknowledgement. "Twinkletoes? How about you?"

Aang had his hands raised, counting on his fingers. "Six, maybe seven? I need to work more on my Pirate's Snarl."

Sokka and Katara said in unison. "No, you don't!"

Aang pouted in response before breaking out in a large grin. Toph turned back to Zuko.

"See? You're matching the Avatar with languages, and he has a head-start from his past lives."

Zuko looked away and muttered under his breath, "I know more."

Toph heard him. "You can speak more than six? How many?"

He sighed and responded, "I'm fluent in six. I can get by in another three. Then I know a little in another… three?"

Silence followed his statement. Sokka broke it with, "You can speak twelve languages?"

Zuko seemed to be counting in his head. Then he admitted reluctantly, "Probably more like… sixteen, if you count some of the dialects. Sorry, seventeen. I forgot about Si Wong Silences."

Suki looked confused. "You forgot what?"

Zuko frowned and seemed a little uncertain. "Si Wong Silences? Language of the Sandbenders? They speak it out in the Desert."

Sokka clicked his fingers and asked, "Is that the one with the weird clicks?"

Zuko replied with said clicks, managing to sound indignant as he did. For clarification he also said, "Yes, it is."

"Why do you speak it?"

Zuko waved a hand. "I don't, not really. I can say, like, a handful of phrases."

Aang opened his mouth to say something when Sokka held up a hand. "Wait, I want to try something."

Then he said something to Zuko in Southern Water Speech. The language flowed like water, yet had the hardness of ice, the harshness of the cold. Zuko frowned at him.

Sokka said, "Well?"

Zuko shrugged and admitted, "I got like, maybe two words. It sounds a lot like Northern Water Tongue, but there's something else there too."

Katara raised an eyebrow at him, forgetting her hatred for a moment. "You speak Northern Water Tongue?"

Zuko shook his head. "That's one of the ones I only know a bit of. My Uncle taught me some before—"

He stopped speaking a moment, then continued a little quieter, "Before the Siege of the North."

Katara's face hardened again and she looked away from him, remembering how he almost got Aang killed in a blizzard. Tears sprang to Sokka's eyes as he thought about Yue. He cleared his throat and blinked them away. Aang frowned when he thought about losing himself to the Ocean Spirit.

That gave him an idea. He said, "I know one language that I know you wont be able to speak."

Then he opened his mouth and sound emerged. Each person there heard something different.

To Toph it was like the grinding of rock, the shifting of Earth. It was like her element beneath her feet, giving her sight.

To Sokka it spoke of something primal, something in his blood. It spoke of the hunt, the chase. Of tracking across the snow and ice. It told tales around the fire and promised the Sun in the darkest winter.

Katara heard the rushing of waves, the flowing currents, and the songs of the Moon as its power flowed through her veins.

For Suki it sounded like the swish of her fans, mixed with the crunch of Earth, and the crash of Water on the shore.

Zuko experienced the heat of the Flame, the touch of the Sun. He felt the scar on his face burn ever so slightly, an echo of his father's flaming fist. He heard the sermons of the Fire Sages, as well as something deeper inside him. A place he normally only felt in the deepest meditations.

Aang stopped speaking and there was a long silence as they all digested what they'd felt.

Katara asked quietly, "Aang, what was that?"

Suki said, "It was beautiful."

Aang opened his mouth to answer when Zuko beat him to it. "Spirit Tongue. That was the Language of the Spirit World, wasn't it?"

Aang nodded. "How did you know? I've only met two people who know it, and one of them was Roku."

Zuko shook his head in wonder. "I-I've seen some wrote down. Old scrolls. But—. I've never heard it spoken out loud before. Not like that. Where'd you learn it?"

Aang shrugged. "I woke up one day, after I got my tattoos, and I just… knew it. Nobody else seemed to know what I was saying, or what it was. Though," he paused before admitting, "Gyatso did seem like he recognised it, but he said he didn't. That was before they told me that I was the Avatar."

Zuko nodded as Katara reached out and squeezed Aang's hand.

Aang shook off his melancholy and asked Zuko, "Hey, Zuko? Do you know how to speak like a Pirate?"

"AANG!"