Like any language, High Valyrian — the Targaryens' mother tongue in Game of Thronesand House of the Dragon— has its own grammar and rules. These come courtesy of linguist David J. Peterson, an avid language creator who constructed High Valyrian and Dothraki for HBO's hit fantasy series. He is also responsible for developing languages for other shows and movies, such as The Witcher, The 100, Shadow and Bone, and Dune.

In a video call with Mashable, Peterson outlined some of High Valyrian's most intriguing qualities (as well as how he created a High Valyrian Duolingo course). When asked about his favorite characteristics of the language, Peterson jumped straight to the fact that it doesn't have definite or indefinite articles like "a" or "the" — something he cited as loving about learning languages like Russian. For High Valyrian purposes, this means that vala (meaning "man")can be both "a man" or "the man," but it doesn't really matter.

Prime Day deals you can shop right now

• iRobot Roomba Combo i3+ Self-Emptying Robot Vacuum and Mop—$329.99(List Price $599.99)

• Samsung Galaxy Tab A9+ 10.9" 64GB Wi-Fi Tablet—$178.99(List Price $219.99)

• Apple AirPods Pro 2nd Gen With MagSafe USB-C Charging Case—$199.00(List Price $249.00)

• Eero 6 Dual-Band Mesh Wi-Fi 6 System (Router + 2 Extenders)—$149.99(List Price $199.99)

• Apple Watch Series 9 (GPS, 41mm, Midnight, S/M, Sports Band)—$299.00(List Price $399.00)

"There are different interpretations where it's more likely that [a phrase] would be translated as having 'the' in English versus 'a' given the sentence structure and how things are flowing," Peterson said. "But you don't have to worry about that when you're using Valyrian. It's so freeing."

Another fascinating element of High Valyrian is its gender system. Nouns in High Valyrian fall into four grammatical genders: lunar, solar, aquatic, and terrestrial. For example, the word embar ("ocean") is aquatic, but the word blēnon ("mountain") is terrestrial.

As someone whose main experience with grammatical gender is the masculine-feminine binary you see in languages like French and Spanish, I was immediately surprised by these different classifications, both by the nature-based names and the fact that there were four of them. Peterson helpfully broke down the High Valyrian gender system, starting with the question of why languages have genders in the first place.

"In designing a language you think, 'Why would someone create this system?' That's really the wrong question to ask," he said. "The right question is, 'Why does this system still exist?' And the answer is, 'Because it's useful.'"

According to Peterson, gender systems help build redundancy into language. Say you're in a noisy room and you can't quite hear what someone is telling you. Based on gendered articles or adjectives, you can get a better sense of the noun you might be missing.

The idea of redundancy helped Peterson develop High Valyrian. "With a language like High Valyrian, where there is a lot of inflection and there aren't a lot of separate little satellite words, [I thought] it would be useful to have a gender system," he said.

However, he decided to eschew the masculine-feminine divide entirely, as he doesn't like that system himself. "Why masculine and feminine? Why are we attributing these sexual characteristics to nouns? That really is just an accident of history," Peterson explained. "If you look at a language like Swahili, Swahili has a robust gender system, but none of the genders are masculine or feminine. It's more like, 'This one is for humans, this one is for places,' things like that."

• The 5 best fantasy shows to watch if you liked 'House of the Dragon' and 'The Lord of the Rings: The Rings of Power'
• How 'House of the Dragon' is different from George R.R. Martin's 'Fire and Blood'
• 'House of the Dragon's ending was foreshadowed in the very first episode
• Who's who in 'House of the Dragon': The Targaryen family tree
• Early 2024 TV deals include several premium Samsung QLEDs and cheap TCL and Hisense QLEDs

With the idea of a non sex-based gender system in mind, Peterson began to think of how he could execute it in High Valyrian. He examined the two phrases of High Valyrian that appear in George R.R. Martin's A Song of Ice and Firenovels: valar morghulis ("All men must die") and valar dohaeris ("All men must serve"). Since valar means "all men," Peterson thought that High Valyrian would be sensitive to ideas of mass versus count — meaning that some nouns would be "mass nouns" (nouns which mean something uncountable, like "water") and others would be "count nouns" (nouns which mean something countable, like "dragon").

When figuring out which nouns fit where, the question became: "Is it a mass noun, or a count noun?" explained Peterson. "And then, does it belong to Class A, the vowel class, or class B, the consonant class? That gives you four genders."

As for the genders' very distinctive names, Peterson was inspired by Arabic and its sun letters and moon letters. In Arabic, if a noun starts with a sun letter, it assimilates the lam sound of the of article al-, but if it starts with a moon letter, there is no change to the al-. The letters' names come from how the Arabic words for sun and moon exemplify these different pronunciations. "The sun" in Arabic is al-shams, and "the moon" is al-qamar. However, only with "the moon" is the lam sound in al-pronounced — "the sun" assimilates the al- and is pronounced "ash-shams," while "the moon" remains "al-qamar." The names for these letters led Peterson to call the first of his High Valyrian genders "lunar" and "solar."

Moving from the moon and the sun to the land and the sea was a natural progression for naming the other Valyrian genders. "They're separated thematically: The moon patterns with the sea, the sun patterns with the land, and then they're separated because the sun and moon are count and then the land and water are mass," said Peterson. "And that's how you you got the names of the four genders."