That's not how inference works! If the people look purple that means your light isn't white. (It might be obvious if Tanya used an optical spell to make a mirror and look at her own face in the light, but she has no reason to do that.)

Making a permanent magical light attached to a pebble is what the fuck? Belmarniss isn't casting the light after the first few seconds, it's just sitting there? Definitely magical, not a lantern or a chemical reaction - it's omnidirectional and entirely even, and the pebble is still visible through it and it's not white-hot - and Tanya could have sworn it's a random pebble the other person just picked up off the ground! How does that work?! Tanya obviously doesn't know all the industrial and civilian spells there are and it's a rapidly evolving field but anchoring a spell, a detectable mana source, to an object separate from yourself has obvious military applications (as decoys, to start with) and she hasn't heard of anything like that??? Now she wants to get a proper translator for Belmarniss and shake her down for her secrets get an explanation of what's going on, even if getting out and back to her unit is objectively still her highest priority.

She will watch the ?spell? on the pebble very carefully and make sure her orb records every detail for later analysis. While being hyperaware of any other use of magic or visible weapons around her, of course. (Knives don't count as weapons.)

If she'll back the fuck off the knife will go in the person's lap but not actually away in its sheath. People examine coins and converse about them and about Tanya some more.

...does the language remind her of anything she's heard before, now that she's heard more of it than the two words "Comprehend Languages"? Does it sound even vaguely Italic, southern-Germanian, Nordic or Slavic? (Tanya doesn't have a great ear for languages but she has a vague idea of what she thinks these language groups all sound like.)

It's hard to tell words apart from their neighbors in a completely unfamiliar language spoken quickly by natives, but she can catch strings like "mekta" and "noth" and "aulin" and "sheb".

That sounds - maybe very vaguely Slavic, by process of exclusion? Definitely not Russy, though.

...she'll wait for them to reach some kind of conclusion on whether they want to even talk to her. Apparently? Certainly as long as Belmarniss isn't leaving.

No one "wants to talk to her" if by "wants to talk to her" she means "suddenly evinces the ability to speak anything she can understand".

Eventually, if she can read body language, the consensus is that she should go with Belmarniss the way they were originally going.

Sigh. What a bizarre, non-actionable situation to get stuck in! At least with all these people here, she's more confident she can find someone if she has to leave Belmarniss later or if Belmarniss doesn't lead her anywhere useful.

She'll follow her. At least she seems to be purposefully leading her somewhere? Or at least going somewhere herself, rather than just exploring the cave system.

They go through a tunnel. At the end of the tunnel, Belmarniss stops and turns to look very seriously at Tanya. She points into the cave beyond, from which some light activity is audible. "Understand," she says slowly and clearly, pointing at herself and her ear. "Not understand," she says, pointing into the cave beyond. "Not." Point at Tanya. "Understand?" (These are all conjugated the same way whether they should be or not.)

"...there are people there who won't understand me?" Tanya guesses. "Or - I won't understand something there that you will and I should watch you for cues?" That's probably too complex for Belmarniss's limited Germanian, how can she say it more simply - "something in there that you understand, I will not understand, I should do like you do?"

Exasperated facepalm. Handwobble, nod, nod.

Can she tell which parts the nods are for and which are the handwobble. Tanya apparently didn't parse the earlier handwobble about there being other people correctly. If she repeats each part separately can she get a yes/no from Belmarniss about it?

Nod for "there are people there who won't understand me", emphatic nod at "watch for cues". Handwobble at "do like you do".

"...fine. If you're sure none of them will understand me, I will follow you and won't try to talk to them." For all Tanya knows Belmarniss told the previous group of weird speleologists to pretend not to understand her, but if she had the local authority to do that (modulo an internal argument) then Tanya won't try to deliberately go against it. (Yet.)

In that case they're going to go through a pig farm, worked by some big blue-skinned people with tusks. The pigs are in pits instead of in pens, but they're clearly audible. There aren't guardrails, though there's plenty of room between them; Niss walks carefully anyway between the open pig pits, which the blue people are pouring mushrooms into and shoveling muck out of. One of the blue people has a tusky blue baby slung on her back and a smaller purple baby tied to her chest.

?????????

Tanya is... going to keep flying behind Belmarniss, apparently, while recording everything she can? (There are no lights here either! This is really not the biggest problem here, and yet!)

Dwarfs definitely exist and it makes some sense that they'd specialize in caves that only very small people can get into. Weirdly pointed ears aren't fundamentally weirder then other facial features. Skin tones are a trick of the light.

Humans do not have tusks. No, not even if they work with pigs all day!!! And these men are as tall as the Legadonian Guard Regiment! What the fuck are they doing raising pigs in a cave with some kind of tooth deformation linked to gigantism?!

The minute they are alone again Tanya demands answers from Belmarniss, with her question being "what was that?!"

Belmarniss blinks at her, and... answers, but, she does it in her own language, so she might be saying "pig farm" or something else.

This is probably not on the shortest path to Tanya getting the fuck out of here but once she is out she would really like some answers, if only for her own peace of mind! What is this, the Brothers Grimm's version of Alice in Wonderland?!

She gestures for Belmarniss to keep going with a frustrated sigh.

...sure, Belmarniss can continue to talk about the pig farm for a bit, can they keep walking? Next up is a mushroom farm; this one has mostly tiny workers but there's one blue guy.

There is no way that any one place would have that many people with dwarfism or gigantism unless they were very rich and collecting them for a traveling circus (i.e. the Legadonians). ...if it's a circus, they could be painting their skin weird colors? 

What kind of circus lives in a huge network of caves and raises pigs in the dark?

If Belmarniss's provided monologue contains answers to these questions it's not understandable to Tanya.

There are more mushroom farms, or more caves' worth of the same mushroom farm.

...

A secret experiment in self-sufficient underground farming? That can't work, right, the fungus needs plant matter that would have to be brought in in very large amounts if you want to get pigs out at the other end...

Eventually they get out of the farm belt, down a long, narrow switchback staircase. Belmarniss calls down the staircase before they start but no one answers and she considers that good enough to go ahead.

Once they emerge from the stairs, they're in a city, a tall stairs-and-ladders-dominated hive of people, little ones and purple ones and tusky ones, running around on various errands, hawking goods out of stalls and climbing up and down and arguing and making out and slapping their children and eating at restaurants and getting measured for clothes and disappearing into side tunnels and reading books. Some of the little ones are carrying lights - magic ones like the pebble Belmarniss cast on earlier, not candles. Purple and tusky people do not seem to be in the habit including if they are reading books and appear to have been doing that since before Tanya's light swept over them.

...

Tanya's suspension of disbelief can stretch pretty far, but she cannot bring herself to believe in an underground city populated by uniformly deformed people who read books in the dark. And who have so many mages - she can sense occasional spells throughout the cavern, none of which her orb recognizes. (They're definitely discrete spells which take the same amount of time to cast every time, including at least one that isn't identical to the spell that produces light.) She can see a few non-magical light sources, flickering like fires, but the small uniform light-spells predominate. The people don't speak any of the major local languages despite there being hundreds of them here at least, and many more by implication. (She's tempted to fly up and illuminate the whole place properly, but - some of them might object?)

This is a scene from some fairy tale. It doesn't fit into the reality Tanya knows. And she has no idea how she could have gotten here, there was powerful magic she didn't recognize and then an abrupt transition, both as she remembers it and in the orb's records. She wasn't even stunned unconscious, the orb would have powered down and recorded that. 

Is it Being X messing with her again? She can't think of any other possibilities but that one is - pretty horrible, actually! Tanya would rather keep risking her life in the war!

...she needs to get out of this cave and into the sky so she can see for herself. Belmarniss agreed there is... something flat (?) above them, right, she doesn't think this cave is her world, and so Tanya's course is unchanged.

Belmarniss watches her take in the city for a moment, and then, when Tanya doesn't do anything that requires immediate attention, beckons her further in.

Tanya is visibly shocked, and on edge, and for a few seconds she moves quickly and jerkily as she speeds up her reactions while she takes it all in (that spell isn't safe to sustain for too long or she'd use it most of the time). But after that she'll follow Belmarniss.