A/n: Incorporating a bit of book canon here. Well, slightly.
What do you think he's doing?
No idea...
Toothless sat with the dragons of Hiccup's friends, all of whom were trying to make sense of what the human was doing. Hiccup had joined the dragons' daily chat, completely unexpectedly, simply taking a seat in the grass beside them and jotting random notes in the notepad he carried around.
Hey! What are you doing? Hookfang asked, taking after his rider in his tendency towards confrontation over subtlety.
You won't find out by asking, Cloudjumper explained patiently, He's human: he can't understand us.
Hiccup smiled slightly as he made another note in his book. Hookfang let out an impatient snort and walked over to the Viking. What are you doing? he asked again, speaking louder and slower - directly into Hiccup's ear.
Hiccup batted the inquisitive dragon away with a hand while continuing to take notes. Hookfang looked over Hiccup's shoulder to see what he was writing, but couldn't work out what was being written.
I can't make out any of these scribbles... Hookfang complained.
That's because you can't read, idiot. Toothless snapped, far less patient than Cloudjumper, Just like Hiccup can't understand you! He doesn't speak the same language!
But I can understand him! Hookfang insisted. He had a point; all dragons could understand the language of the Vikings as well as their own, it was just that the understanding wasn't mutual. I thought it was just my rider, he continued, but it looks like yours is just as stupid!
Hiccup is not stupid! Toothless growled, coming over to defend his friend. He placed a protective wing on him as though it could do something to stop Hookfang's insults, Vikings just can't understand dragons!
"Calm down, bud," Hiccup soothed, rubbing Toothless's back calmly, "It's okay."
Toothless relaxed. Leave it to his rider to help him calm down, even when he had no idea what irked him so. Or perhaps he did; Toothless had noticed that Hiccup seemed to always know what was wrong, like he was somehow surpassing just the ability to read into a dragon's body language. Whatever the reason, it was lucky that Hiccup always knew the right thing to say. Thanks.
"Don't mention it," Hiccup said, leaving Toothless to wonder exactly how much his friend actually knew of the way dragons spoke. He had an uncanny natural talent for understanding dragons, but surely he must be having some sort of lessons, or even teaching himself about it? It didn't matter now; Toothless vowed to look into the issue later. Now, what had they been talking about before his human so rudely interrupted?
The next day, Hiccup sat in on the dragons' talk again.
"Hey bud," he greeted as he walked into the clearing, relaxing into the same spot he had yesterday.
Hi. Toothless replied, watching Hiccup take another note. Was he writing down his responses? Whatever he was doing, it looked tedious and difficult. Nothing a quick flight couldn't distract him from.
Toothless?
Oh, great. Now his rider had managed to distract him enough to pull him from the conversation. Again. Sorry, he apologised, I was just -
Distracted by Hiccup? Cloudjumper laughed. Despite the dragon's newfound respect for Toothless after him becoming the alpha, Cloudjumper still found the younger dragon's antics amusing, especially when it came to the illogical friendship that had ended the war against dragons. It's okay; if you want to go for a flight now, we'll all understand.
"No!" Toothless looked over at Hiccup confusedly, bemused that the Viking had spoken for him. "I can't go yet; I'm just getting the hang of translating!"
What? Cloudjumper said slowly, tilting his head in confusion, Translating?
"Well, yeah," Hiccup said casually, "What did you think I was doing, sitting here while you all talk? I'm trying to learn your language. I might not be able to speak it, but looking after dragons would be much easier if I could understand them fully."
I see... Cloudjumper nodded thoughtfully, Well, I'd be happy to help.
You're trying to understand us? A young terror asked, bouncing onto the Viking's head, I wanna help! Oooh, can you tell what I'm saying now? Trees! Dragons! Do you know the word for fish? That's important! How about salmon? Cod? Eel?
"Slow down!" Hiccup laughed, taking the tiny dragon off his head and scratching his head slowly. "I got a bit of that. Lost you around help..."
Literally a bit, then. Toothless joked.
"Very funny, Toothless," Hiccup said, grinning. "Now, are you gonna help me with this or not?"
"Why do we have to be at the academy again?" Ruffnut complained, leaning against Barf and Blech.
"Cos... I have no idea!" her twin countered, punctuating the sentence with a light - for the twins - punch in the arm.
"We're here because Hiccup said so," Astrid reminded them pointedly. "Hiccup the chief."
"Hiccup your boyfriend." Ruffnut argued.
"Okay guys, clearly you're wondering why you're here," Hiccup saved the group from any further arguing, "So I'll tell you: you're going to learn Dragonese."
"Dragon disease? Leave that to the healer," Tuffnut dismissed, waving his hand as he prepared to mount his head of his shared dragon.
"No, stupid," Ruffnut whacked her twin on the head, "Dragonese."
"Yes," Hiccup agreed, "And it's the language that dragons speak. If you don't want to learn it, you can leave now."
Ruffnut and Tuffnut shared a quick glance before hopping on their dragon and flying off. Snotlout looked indecisive for a moment, then mounted Hookfang and left without another word.
"So, it's just you two?" Hiccup confirmed. "Somehow, that doesn't really surprise me..."
"Let's get on with it then!" Fishlegs was practically shouting in his excitement, "Finally, I'll be able to understand Meatlug completely!"
No one understands Meatlug, Toothless joked, invoking laughter from Hiccup.
"What's so funny?" Astrid asked, noticing the exchange between the two.
"If you pay attention, you'll be able to work it out yourself in a few weeks!" Hiccup said brightly, "Now, let's start with the basics... Toothless, say 'fish'."