He can probably move fast enough no human will actually notice he's naked but whatever, he'll get one of those baggy suits and lose it if it becomes too annoying underwater.

Somewhere he can stash his clothes to dry?

Dryer service: 6 Kava per item.

Shoes, socks, jeans, underwear, T-shirt, and then he goes under.

Make sure to keep this magic numbered tag to match up with his stuff again later.

Luckily the swimsuits have button pockets, for some reason.

This is definitely the merfolk equivalent of chinatown. Mazes of underwater stone constructions, kelp forests, and so on. Major open areas have arrays of mirrors on the surface directing nice light down. There are merfolk buskers and street performers - the language is a lot prettier underwater, it doesn't sound like choking anymore.

Can he speak it with his van-kire throat?

...Mostly. Two sounds he can't quite manage but he should be intelligible.

Do they have books or something like that with a diagram of what their throat looks like from the inside?

Merfolk mostly don't do books. He could probably work something to make that weird click and low warble on his own though.

He tries something. Does it work?

Close enough to be in 'weird accent' range.

Cool, he'll take it, and tour around some more, asking questions about architectural styles and economic activities and art and science and music and...

Merfolk have all these things in various flavors.

The common theme is being very communal and rather hunter-gatherer, culturally. Merfolk architecture wouldn't work above sea but they can fake the same style like so... Would he like to buy some souvenirs, obvious tourist that he is? Perhaps authentic mer cuisine?

Unfortunately he does not eat, but he might want some souvenirs! He's curious about how other tourists visit, though, and he's especially intrigued by the differences in psychology.

Water-breathing amulets. 10 Kava an hour rental. None of these merfolk are psychologists, so he might have to ask specific questions.

Well, he's curious about stuff like child rearing, toys, games, economic activities, jobs, social structures, religious views, political structures, hobbies...

Merfolk infants don't know who their genetic parents are. They live in a nursery and mer who would be good to take care of them and teach them something suited to their talents start taking care of them more often as they get older and start working. They tend to end up doing what they're best at as work even if they don't like it, for the good of the group.

They don't seem to like complicated or individual toys, preferring big playground equipment type things. Most games are cooperative, competitions between two large teams or a race to finish some big task against the clock.

They are more hesitant to talk about politics and religion. There is almost no class divide. The greatest aspiration is being recognized as the best at something, or a leader of one's tribe. On the other hand, tribes in close proximity such as in this strange human city tend to fight occasionally. 

They are bemused by humans' individuality and even more bemused by the idea of hereditary monarchy. As for hobbies... Sparring, making murals, dancing, music, magic, swim races, telling stories...

They are a fascinating people and Sadde agrees humans are very strange! He hopes he did not offend them asking these things, he does not mean to treat them like "exotic foreigners" or something like that, he is just very curious about how different species' native psychology works! He will purchase a couple of souvenirs.

What kind of souvenirs? Artful glass spheres with detailed scenes inside? A magic tambourine-like thing that promises to sound the same out of water? Kelp derived slick waterproof t-shirt?

The glass spheres sound cool, but—do they have interesting music-making things that only work underwater? Those would be pretty interesting to have.

Sure, he can buy water instruments. Proper ones are a bit expensive.

How about a thing humans would call a water-flute? A set of streamers with finger toggles you drag behind you that change tune when you speed up or turn? Almost a swimming piano, sort of.

Oooh! That looks cool, and he bets he can have more fun with it than humans can.

Probably, yes.

A cheap one made of carved shells and string is 850. A quality one made from whale ivory and shark teeth, and a couple of enchantments against wear, is more like 3000. There are options in between, too, and he can try the cheapish ones out.

Are there any structural differences between the cheap ones and the more expensive ones, or is it just materials and enchantments?

The expensive ones have more keys, 14 compared to 10.

Are the structural differences from ten to fourteen a straightforward extension?