Three months after Daniel's death, his journals are still largely untranslated. The linguistics department just shake their heads apologetically. Sure, the entries usually start off in English, but after that, who knows? His writings are peppered with phrases and blocks of text in strange dialects, no doubt chosen because their nuances are more compatible with whatever idea he's struggling to explain. It would take a team of experts years to go through and decipher it all, and even then they'd probably miss the subtexts and implications of the more obscure references. If you want the research and information from Dr. Jackson's journals, they conclusively write in their final reports, you're going to need someone as brilliant as he is.
Luckily, there's a recently-moved washed out linguistics genius currently residing in Seacouver. It takes one phone call to the president to set in motion a chain of events that will send this young graduate student Pierson over to SGC, including a diplomat dispatched to acquire official approval from the United Kingdom to use one of their citizens as an asset.
Pierson arrives with a ratty suitcase and a wide-eyed curiosity that marks him for a scientist. He attacks the preliminary tests with gusto, smiling in admiration as he transcribes the declassified materials. "This passage here, the phrasing is particularly nuanced," he enthuses. "Whoever wrote this really knew his stuff. Who did you say these journals belonged to?" The SFs guarding him stare back with stony indifference.
Pierson shrugs good-naturedly and uncomplainingly (for a scientist, at least) goes about his work. That work ethic doesn't change when the brass finally approves his security clearance, once the allowance is made for Pierson's initial aliens are real revelation. In return, the SGC personnel are mostly happy to ignore him when the weedy boy begins sitting where one of their best and brightest used to work, drinking Daniel's coffee and using his office supplies as he steadily works through years of journals.
When Daniel comes back (and he's been dead few enough times that the experience is still greeted with wholehearted relief and many avows of never again), Dr. Pierson leaves as easily as he came into the program, smiling a little sadly as he bids goodbye to the SFs guarding the lab. While he's packing, however, he pauses and takes out a leatherbound journal. "I've read all of his journals," Pierson says to the guards as he leaves it on the desk. "He might as well read one of mine."
It takes a few months for Daniel to unbury it from the paperwork that had been dumped on his desk post-resurrection, and by that time Adam Pierson has long since disappeared from his part-time job in an obscure historical society. Daniel runs his fingers over the engraved symbols on the cover, smiling at the intricate swirls and dips of the language. Hello, Daniel, it says. "Hello, Methos," Daniel murmurs. "Long time no see."