"Gabh síos ort fhéin!" John swore, as his gun jammed. It was instinctive, a phrase that only passed his lips in this instance, though he was at a gun range in London, rather than pinned down in a nameless town in Afghanistan.

"John!" Sherlock admonished him.

"What?" John said absently, examining his gun.

When Sherlock failed to speak again, John looked at him. Sherlock had put his own gun down and was standing, arms crossed, hip cocked against the bench. He was looking consideringly at John, his brow furrowed. John didn't bother to ask, knowing by now that Sherlock would explain himself when he was ready, or had gathered sufficient data to make an observation.

"Usually you swear in English." Sherlock noted, and again John ignored him.

"You learned to swear in a foreign language in the Army," Sherlock said with the lazy inflection he used when he knew he was right.

John grinned smugly at him, without answering. In the four months they had known each other, John had made a mental list of things that irritated Sherlock. Not having his observation confirmed was high on the list, and John occasionally took advantage of that fact when he felt Sherlock needed it. He kept his attention ostensibly on his gun, though he could see Sherlock shifting in annoyance to have the deduction hang in the air. He hadn't mentioned the specific language, John noted.

"What language was that, then?" John asked Sherlock, and was rewarded with a scowl, which only served to widen John's smirk even further. He was sure Sherlock wouldn't be able to place it, and he knew that would drive him up the wall. It would be interesting to see just what lengths Sherlock would go to see what language John was speaking and where he learned it.

A week later, John was updating his blog when Sherlock swept into the room. He immediately came over to sit on the floor next to John and stuck his phone in John's face.

"Say it again." He demanded.

John blinked, using all his considerable self-control not to reflexively punch Sherlock in the face for invading his personal space so abruptly. "I beg your pardon?" He asked mildly, knowing his deliberate ignorance would exasperate Sherlock.

"The thing you said, the 'garv see us worth hey'," he glared at John's derisive snort of laughter, "say it again!"

John looked at him, his eyes calm. "Why?" he asked.

Sherlock looked at him again, clearly annoyed. "Just do it, John."

"No," John refused, then his eyes sparkled, "Not until you tell me why." On a whim, he added, "And you could say please."

Without another word, Sherlock stood up and stomped out of the room. John grinned to himself. This was proving to be very entertaining.

Five days later, Sherlock burst into the bathroom as John was brushing his teeth. He narrowly avoided getting toothpaste spit over him as John turned around to see what the hell was going on.

Sherlock stood stock still, glaring daggers a John, until John said, "Yes?" He had learned that the mild mannered, slightly confused persona was the best when Sherlock was itching for a fight. He couldn't fight against it, so he would either stomp out or sit and sulk, either of which allowed John to get on with his day. The few times John had tried to argue, or placate him, or even ignore him, Sherlock had followed him around, basically harassing him and making any productive enterprise impossible. So John 'went to his happy place', as his sister would say, and just let Sherlock work it out on his own. Meanwhile, the glare went on until John was tempted to speak again.

Before he got the chance, Sherlock said in a growl, "Please will you repeat the phrase you said at the gun range."

John nodded, then prompted, "Because…"

Sherlock sighed dramatically, finishing the sentence as though the admission pained him, "Because I can't repeat it accurately and I don't know what language it is."

John nodded, rinsing his mouth out before saying, "Gabh síos ort fhéin."

Sherlock looked outraged, sputtering, "I wasn't ready!"

Tempted though John was to keep teasing Sherlock, he could see that the other man was at his limit on this particular puzzle, so he consented to follow Sherlock and repeat the phrase clearly into the voice recorder on Sherlock's phone. Finally satisfied, Sherlock disappeared without so much as a thank you. John wondered how long it would take him to pin down the language. He shrugged, remembering that this was only half the challenge.

Three days later, Sherlock woke John at five twenty three AM, triumphantly saying, "You were speaking Connacht Irish, a dialect of Irish Gaelic, spoken primarily by those native to western Ireland. The distinctive pronunciation of lengthened vowels and reduced endings differentiate it from other dialects of the same language. The phrase roughly translates to 'Go fuck yourself'."

John looked up at him, blurry eyed. Sherlock's hair was dishevelled, eyes wide, mouth hanging open as he waited for John's assessment of his brilliance.

"Very good," John yawned. "How did I know it, though?" Sherlock, who had started preening at the initial praise, looked put out.

"I worked out the first part," Sherlock objected. "You might as well tell me the rest, it's easy enough to find out, what with public service records and such."

John sat up against the headboard and rubbed at his eyes, wondering if he should tell Sherlock. It was odd, actually, that Sherlock didn't want to find out for himself – that tended to be one of his defining features, the constant stretching and testing of his ability to find information. A flash of perception, and John grinned. "You don't want to call Mycroft." He stated, and Sherlock scowled again at him, knowing his cover was blown.

"I can do it without Mycroft," Sherlock said almost sulkily.

John chuckled. "If you do figure it out without Mycroft," he said, "I'll tell you the story about each and every scar on my hands."

Sherlock's eyes lit up at this. "Really?" he asked, and John was reminded of nothing more than a small boy at Christmas. Sherlock had been fascinated by John's hands ever since they had met, the BSL they both practiced making their hands a focus of several conversations. Sherlock had been insisting John tell him how he had come by the scars, of which there were several. John was equally flattered by the interest and a little wary – it was an intense interest in detail other people wouldn't even notice, but he knew Sherlock focused on minutiae, and only those he deemed worthy of his attention. Either way, it would motivate Sherlock to work on this problem without Mycroft, which should earn John a few more days of blissful quiet as Sherlock worked obsessively through public records or harassed police officers into searching for John's old Army mates.

The next day, Sherlock came home late in the afternoon, quietly mounting the stairs and sitting in his chair. He had stopped to hang his coat and scarf up, and was clearly waiting for John to finish what he was doing before he spoke. The consideration was so unlike Sherlock that John was a little concerned. He looked up into Sherlock's eyes, though, and saw compassion and just a shade of guilt.

"You know, then," John said, marking his page and closing the book with a gentle thud.

Sherlock nodded.

"One day," John said. "Impressive. Who did you threaten at the Yard to open their files for you?"

Sherlock looked levelly at John, before saying quietly, "I went to see Harry, actually."

John's eyebrows rose. He was surprised at this, being sure Sherlock had fixated on the Army connection, even though John had been swearing at jammed guns long before he had donned the uniform. "I was wondering how that connection might have been in public records."

Sherlock nodded, then asked more hesitantly than John had ever heard, "Do you want to tell me…" he trailed off.

John was surprised to realise that he did want to share this with Sherlock. Few of the people in his adult life had heard the story, but for a reason he couldn't fathom, he wanted Sherlock to understand this about him.

"I first learned to shoot from Cormag, he lived in a little house at the edge of our estate. He used to hunt rabbits and foxes mainly, and I was looking to get out of the house." John knew Harry wouldn't have explained this to Sherlock, but he expanded, "Dad drank. When he drank, he got mean, and it was better not to be around." He shrugged, and the sharp intake of breath from Sherlock confirmed his assumption that Harry had continued to protect their father even now.

"Harry didn't see the worst of it, she was boarding at our school, like most of the Deaf students. I wandered a lot, and one day Cormag almost took my head off, thought I was a rabbit or something." John smiled mirthlessly at the memory, before continuing colorlessly, "He shouted at me in Gaelic, then told me in English I'd better be on the other end of the gun if I didn't want to get shot. His eyes weren't great, so he taught me to clean his guns for him, and in return he taught me to shoot. He was Gaelic down to his bones, spoke a lot and swore a lot in his native language, and I picked up the habit from him."

Sherlock shifted, and John, startled out of his reverie, looked over. The detective clearly had a question but was uncharacteristically reluctant to intrude. John caught his eye and raised his eyebrows, inviting the question.

"How did Harry know about it?" Sherlock asked.

This memory was actually funny, and John grinned a genuine grin at it. "I almost shot her, as Cormag almost shot me," he said, but she couldn't hear Cormag yelling at her, so I barrelled down to sign at her. I had to try and translate some of his words and it was" he shook his head, "difficult."

Sherlock smiled a little uncertainly. "Like bad subtitles?" He suggested.

John laughed, nodding. "Exactly." They sat in silent for a few minutes, Sherlock digesting the new information, John reliving parts before packing the memories away.

"Why did you go to so much trouble to find that out, Sherlock?" John asked suddenly.

Sherlock looked at him sharply. "Because you wouldn't tell me." He answered simply, as though it were obvious.

John blinked. "But I didn't tell you…" he trailed off.

Sherlock smiled carefully back. "You didn't tell me because you wondered if I'd go and work it out. You wanted to know how much effort I would put into finding out this trivial thing about you. You know I only put effort into things I think are worthwhile." Sherlock looked calmly at John as he explained John's reasoning, and John felt his face flame. He hadn't even known that was his reasoning, yet it made perfect sense once Sherlock outlined it.

He shook his head in amazement. "How come I didn't even know that until you explained it?" He asked.

Sherlock sat back, his turn to look smugly at John.

"Because you're an idiot. No, no no, don't look like that. Practically everyone is. Ooof!" Sherlock's exhalation as John tossed a cushion at his head was the last sound for a long, comfortable time.