Short story about humans as beasts of burden for another race, read about 30 years ago

Question

Short story or possibly book where humans on a planet are work animals for a different race. It turns out that it was a human colony that was overrun by this race a long time ago. I believe it is the song "Twinkle Twinkle Little Star" that has importance in this story. A man and woman end up entering tower that turns out to be human space ship and launching it. They are on their way back to Earth with a message "colony {colony name} needs assistance."

Answer 1

This is The Silk and the Song (1956) by Charles L. Fontenay.

A preview may be found here.

It was released in The Magazine of Fantasy and Science Fiction, July 1956

It's about a group of humans who are enslaved by aliens, generations after a disastrous landing on their planet. They teach their kids a song to the tune of "Twinkle, Twinkle, Little Star" which turns out to contain instructions for operating the dormant rocket.

Twinkle, twinkle, golden star,

I can reach you, though you’re far.

Shut my mouth and find my head,

find a worm that’s striped with red,

feed it to the turtle shell,

then go to sleep for all is well.

Answer 2

This is also a partial match with The Lani People by Jesse F. Bone.

The Lani are humanoid alien species with long tails on the planet Kardon, where they are kept as work animals. They are used to perform manual labour on farms etc. and even such things as serve food in houses and act as assistants to doctors. They are highly attractive and apparently all female.

A new vet, from an old established Earth colony called Beta, is employed to look after the Lani on the island where they are found/kept and he discovers that the Lani are intelligent, completely anatomically human except for a long tail, and have a spoken language, which he hears the Lani using to recite/sing some song he doesn't know, but which sounds familiar. He is assured that tests have been performed which showed "not human" and the Lani are legally recognized as non-human aliens by the courts on Kardon, so can be used as animals.

The vet discovers that Lani are not all female and the males are all kept isolated on a secret island to stop competitors breeding their own Lani. Looking down a microscope at the fluid he receives for artificial insemination he finds out there are males and the fluid is semen/sperm and from this he works out that the the Lani are human. The vet also becomes intimate with his Lani assistant and gets her pregnant, something that has never happened with other human men who have had sex with Lani. It turns out that as a Betan he has a mutation that also causes him to have a short tail and this is enough to make him genetically compatible with the Lani.

His Lani assistant teaches him some of the Lani language learned as songs and he recognizes it as a garbled version of English catechism of the creation story in Genesis:

Without warning her voice changed to a rhythmic, cadenced chant that was almost a song. Her face became rapt and introspective as she rocked slowly from side to side. The rhythm was familiar and then he recognized it—the unintelligible music he had often heard coming from the barracks late at night when no men were around—the voiceless humming that the Lani sang at work.

First there was Darkness—starless and sunless

Void without form—darker than night

Then did the Master—Lord of Creation

Wave His right hand, saying, “Let there be light!”

The tale also tells of the founders of the Lani. These founders were called "Ulf and Lyssa", and the story tells of Ulf trying to communicate with "Heaven" from a tower:

He went into Lyssa’s tower—where Ulf and Lyssa tried to call Heaven—and with his foolish meddling set the tower alight with a glow that all could see.

He then finds out that the tower was destroyed by the "discoverer" of the Lani, the ancestor of the current owners after he was attracted to it by the signal sent by Ulf. He also discovers that Ulf and Lyssa came in a "God egg" which it turns out is a landed spaceship with a very old form of drive on a hill nearby. The old drive leaks radiation when in use and in its landed form. The vet fixes up the spaceship and launches himself and his assistant back to Beta, where he gets for freedom of the Lani from slavery by recognition of their human status.

The tails that Lani have are a result of mutation from a founder effect and the radiation Ulf and Lyssa were exposed to as they came through space from Earth using their old drive:

Kennon nodded. “Now let’s check—oh! oh! what’s this?” He pointed to a metal-backed book lying on the control panel.

“It looks like a book,” Copper said.

“I’m hoping it’s the book.”

“The book?”

“Yes—the ship’s log.

And that’s what happened to this ship. According to this log it was bought by Alfred and Melissa Weygand—a missionary couple with the idea of spreading the Christian faith to the heathen.

“Alfred and Melissa—Ulf and Lyssa—they were a part of this ancient explosion that scattered human seed across parsecs of interstellar space. It seems that they were a unit in a missionary fleet that had gone out to the stars with flame in their hearts and Gospel on their lips to bring the Word to the benighted heathen on other worlds.”