Citizen of the Galaxy by Robert A. Heinlein

ducked his head and pressed his palms together. “I am honored. My name is Thorby, son of Baslim.”
    “The pleasure is mine, Thorby. Call me 'Margaret.' My title doesn't count here anyhow, since it is not a ship's title. Do you know what an anthropologist is?”
    “Uh, I am sorry, ma'am -- Margaret.”
    “It's simpler than it sounds. An anthropologist is a scientist who studies how people live together.”
    Thorby looked doubtful. “This is a science?”
    “Sometimes I wonder. Actually, Thorby, it is a complicated study, because the patterns that men work out to live together seem unlimited. There are only six things that all men have in common with all other men and not with animals -- three of them part of our physical makeup, the way our bodies work, and three of them are learned. Everything else that a man does, or believes, all his customs and economic practices, vary enormously. Anthropologists study those variables. Do you understand variable'?”
    “Uh,” Thorby said doubtfully, “the x in an equation?”
    “Correct!” she agreed with delight. “We study the x's in the human equations. That's what I'm doing. I'm studying the way the Free Traders live. They have worked out possibly the oddest solutions to the difficult problem of how to be human and survive of any society in history. They are unique.” She moved restlessly. “Thorby, would you mind if I sat in a chair? I don't bend as well as I used to.”
    Thorby blushed. “Ma'am . . . I have none. I am dis --”
    “There's one right behind you. And another behind me.” She stood up and touched the wall. A panel slid aside; an upholstered armchair unfolded from the space disclosed.
    Seeing his face she said, “Didn't they show you?” and did the same on the other wall; another chair sprang out.
    Thorby sat down cautiously, then let his weight relax into cushions as the chair felt him out and adjusted itself to him. A big grin spread over his face. “Gosh!”
    “Do you know how to open your work table?”
    “Table?”
    “Good heavens, didn't they show you anything?”
    “Well . . . there was a bed in here once. But I've lost it.”
    Doctor Mader muttered something, then said, “I might have known it. Thorby, I admire these Traders. I even like them. But they can be the most stiff-necked, self-centered, contrary, self-righteous, uncooperative -- but I should not criticize our hosts. Here.” She reached out both hands, touched two spots on the wall and the disappearing bed swung down. With the chairs open, there remained hardly room for one person to stand. “I'd better close it. You saw what I did?”
    “Let me try.”
    She showed Thorby other built-in facilities of what had seemed to be a bare cell: two chairs, a bed, clothes cupboards. Thorby learned that he owned, or at least had, two more work suits, two pairs of soft ship's shoes, and minor items, some of which were strange, bookshelf and spool racks (empty, except for the Laws of Sisu), a drinking fountain, a bed reading light, an intercom, a clock, a mirror, a room thermostat, and gadgets which were useless to him as his background included no need. “What's that?” he asked at last.
    “That? Probably the microphone to the Chief Officer's cabin. Or it may be a dummy with the real one hidden. But don't worry; almost no one in this ship speaks System English and she isn't one of the few. They talk their 'secret language' -- only it isn't secret; it's just Finnish. Each Trader ship has its own language -- one of the Terran tongues. And the culture has an over-all 'secret' language which is merely degenerate Church Latin -- and at that they don't use it; 'Free Ships' talk to each other in Interlingua.”
    Thorby was only half listening. He had been excessively cheered by her company and now, in contrast, he was brooding over his treatment from others. “Margaret . . . why won't they speak to people?”
    “Eh?”
    “You're the first person who's spoken to me!”
    “Oh.” She looked