DZ can go as fast as Reika likes; she does start out with an assumption of normal human learning capacity but very quickly picks up on the difference and switches over to teaching her the same way she'd teach another droid. She starts with the most basic necessities to get by - yes and no, simple question and answer words, pronouns, and the like, and then methodically works through the most common hundred, five hundred, and thousand words in the language, interspersed with grammar lessons as examples of different parts of speech come up.

That done - and it takes a couple hours - she stops to ask what they'd like her to focus on next. "I might need to skip the section about starships and space travel, though. It translates very poorly, and I don't understand the topic well enough to explain the terms in depth."

"Those don't seem to be concepts we have yet, yes," Reika says. 

"Now that we know it's possible we might look into turning research to it, but I imagine if we do invent space travel at that point it'll be easy enough to re-exchange vocabulary with whoever we meet. Though I suspect something relying on chakra, especially seals, will be easier for us," Tobirama comments. "Summoning techniques exist; I'll have to devise a test for if they work faster-than-light."

"Yes sir. Deskyl might be able to help with that; it's not her specialty, but she is an engineer, and fairly well-read."

He nods. "My specialty is seals and inscribed techniques. Those cover anything we'd use of our own magic."

Modifying his Flying Thunder God technique to work across massive distances, so that one object would be moved to a specific seal, is a consideration, as is moving in and out of summoning realms, or a seal that pulls specific objects to it... Of course, he's unlikely to crack immortality in his lifetime, and his brother keeps shooting down his research into necromancy, so it'll probably be something to leave to a successor to finish, but he can start. And even small steps forward will benefit the village.

"Yes sir."

He'll indicate their most important topics - clearly still with a focus on things useful in diplomacy and negotiations.

Tobirama also practices fine-tuning his own senses to Deskyl's condition, so he should have warning before any major changes, though whatever magic she has doesn't map perfectly onto chakra so he's not getting nearly as much detail as usual. It's like he's seeing her in his peripheral vision, really.

(He stays in silent communication with his clone and Mito, as well, and occasionally checks on the other two foreigners.)

Even just from what he can see, she's in terrible shape. Not physically; she's fine, physically, except for being a bit out of shape. But mentally - the metaphor her state evokes is that of a beach after a major storm, scoured to the bedrock. She's recovering - quickly enough for it to be visible, just barely, if he watches patiently enough - but from an injury so profound that it's shocking she survived at all.

Unfortunately, even if she seemed likely to trust them with her mind, the way her magic works is different enough he's not confident even the most skilled of Yamanaka could help without possibly unacceptable risks.

(He's felt similar mental damage before, back when his clan was at war with the Yamanaka and Uchiha, and getting caught in either's mental techniques could easily be a death sentence. He's aware humans are resilient. He's also aware that recovery can be slow, if it happens at all.)

He's patient, though, unusually so even for a ninja.

There's not much to see; she's at rest, in a sense more complete than just sleep.

Her barely-visible magic seems to be doing something to, or with, or about, Desuka, though.

He'll start more carefully monitoring Desuka for any damage or change.

She's fine as far as he can tell, though quite concerned about Deskyl.

He'll leave it for now, though he'll continue monitoring the situation.

"Would this be a good time for me to feed Deskyl, ma'am? I expect the next section of vocabulary to take a few hours."

Reika glances at Tobirama.

"That's fine," he says.

"Thank you, sir."

DZ prepares a bowl, and Desuka takes the opportunity to go get something for herself as well. When she breaks contact with Deskyl, the woman's magic recedes, and her healing slows.

Hm.

"Deskyl's magic seems to be reacting to Desuka, specifically, in a way that speeds up her healing," he says to DZ. "Do you know anything about that?" A pause, and: "My main concern is risk to Desuka."

"I'm not sure, sir - it seems unlikely, especially if you can sense it and Desuka seems fine; some Sith techniques do drain energy from others but it's usually obvious, and as far as I know Deskyl has never learned those techniques."

He nods. "There's a variety of things it could be. Still, Desuka, there is a mostly unknown risk - are you alright with taking that?" He's not going to tell her she can't, of course.

She considers it. "Obvious?" she asks DZ.

    "Yes ma'am. Most Sith techniques are unless the Sith is specifically shielding them."

She nods, and considers for another moment. "Okay."

He nods. "Eventually, I'll want to turn my attention to village matters," he says, "Though I don't need to leave quite yet. Reika, are you alright with staying longer?"

She hums. "Yes, Lord Tobirama. I can stay up a few days without issue. I'll make sure the children get sleep, as well."

Wryly: "I think if they want to stay up you're unlikely to win that argument, and they're old enough to make that choice. I'll have bedding sent if they feel like sleeping, but don't push it." He remembers being that age, and suspects the kids are probably better at staying awake than Reika will be.

She inclines her head. "Yes, sir."

DZ feeds Deskyl, patiently enough to be neat about it, and then gets back to the lesson, now focused on vocabulary useful for making treaties.

He'll stay through that, then make his excuses and leave. By now he's fairly certain he'll know before Deskyl wakes properly, and he has office work to do. He tells them he'll be back in the morning, though.