Rediscovery is part of the Darkover Series, by Marian Zimmer Bradley. Terrans (Earth-born humans) searching the universe for a colonizable planet find Darkover, and realize that the people there are from a lost colony of early human space explorers. This is a very important book in the series, as it ties Darkoverans back to their earthy home. For some Terrans, being among the Comyn helps them use and train their laran, which most of them were unaware of possessing. These first interactions sets the stage for future interaction between Terrans that Darkoverans.
It was an interesting book. I’ve gotten used to Darkover novels having no contiuance of character or story other than hereditary struggles or genealogical myth. But in the novels discussing the Free Amazons and the Terrans, there are so many common characters that you get the type of story continuance that I would have loved in the novels about The Founding and The Age of Chaos. It’s a little disconcerting after convincing myself that one story about a person, family, or situation was all I was going to get. Ever.
MZB is one of my favorite authors. This is the first I’ve read of Mercedes Lackey. I do recommend this book, especially if you have interest in reading the Darkover series, though I would start with Darkover Landfall.

“Ah,” he said, and then continued mind-to-mind. Shall we go a little apart then, so that people have the impression that we are speaking aloud? I sense that you are not comfortable with the notion that your fellow star folk know we can speak this way.
“I should like to practice on you,” she said openly, in fumbling and awkward Darkovan, “If you do not mind.” And answered him, That would make me feel a little better, if you would. You are right. There are those among my superiors who think that we who claim to speak this way are trying to practice some deception on them.
Deceiving them, or yourselves? he asked wryly.
Both. Elizabeth–some folk think she is–unstable.