In “A Dance with Dragons,” the penultimate episode of Game of Thrones Season 5, Daenerys is surrounded by the Sons of the Harpy, an insurgent group bent on her murder. It looks like they’re going to move in for the kill when, wonder of wonders, Drogon the dragon descends from the sky and lights the Sons up like a pile of cheap birthday candles. Unfortunately, Drogon is wounded in the resulting scuffle, so Dany climbs onto his back so she can fly him out of there. Before he takes off, she whispers a single word: “Valahd.”

If viewers didn’t have the closed captioning on, they may not even have realized that this is what Dany said. Even David J. Peterson, the linguist responsible for creating the made-up Dothraki and Valyrian languages for the show, thought she said “fly,” which was the English-language command she gave Drogon in the corresponding scene from George R.R. Martin’s A Dance with Dragons. Weirder still: Peterson, who translates the Game of Thrones scripts into Dothraki and Valyrian as needed, had recommended to the production that, at this moment, Daenerys say “Sōvēs,” which is the Valyrian word for “fly.” (Incidentally, Dany whispered the plural of “Sōvēs” to her dragons in the Season 3 finale right before they took flight, so there was precedent for using that word.)

Clearly, some wires got crossed. What happened? Well, according to Peterson, although the word “Sōvēs” was in the script, Emilia Clarke said “fly” when filming the scene. Given the hubbub of the production, that’s understandable. As Peterson points out, “Scenes get busy, lots of activity, sometimes a word gets forgotten and that take turns out the best, etc.”

Later, when Clarke went back to dub over some of her lines in a process known as Automated Dialogue Replacement (ADR), the producers tried to add the Valyrian word “Sōvēs” back in. The problem was that Clarke’s mouth wasn’t making the right shapes, so they ended up going with “Valahd” instead. That, of course, raises another question: if “Valahd” isn’t the Valyrian word for “fly,” then what is it?

Per Peterson, “Valahd” isn’t a Valyrian word at all. It’s Dothraki. Literally translated, it means “horizon,” but it’s also an informal command Dothraki riders give to their horses when they want them to move. So, when said to an animal, it basically means “Giddyup!” or “Hya!”

Weirdly, even though it wasn’t the writer’s original intention, I think Daenerys breaking out the Dothraki language at this moment is oddly appropriate. After all, she did the bulk of her growing up when traveling with Khal Drogo’s khalasar—that’s when she learned she had leadership potential, when her dragons were born, and arguably the last time she was really happy. Lately, she’s been curbing her Mother of Dragon-ish instincts to play political games in Meereen, and seeing her baby dragon all grown up and unleashing the hurt must have brought some of those old feelings back. Maybe seeing Drogon’s wanton destruction of the Sons of the Harpy even reminded her of Drogo, Drogon’s namesake. Her use of the Dothraki word also makes for a nice segue into the next leg of her journey, which will find her traveling with a khalasar once again.

For more details on the this translation mistranslation, read Peterson’s full post over on his blog.