Peterson said he was able to construct more than 4,000 words out of the handful of phrases in Dothraki that were in the books. He had been associated with the Game of Thrones TV series since 2011, after winning a competition for the actual creation of a language for the pilot of the show.
He said that to construct the words that he used for his presentation for the pilot show, he gathered all the Dothraki words that were in the three books and chronologically analyzed them to pinpoint the syllable shapes, the word shapes and the sounds that would be created. When he had them figured out, he was able to create more syllable shapes and ascertained the types of consonant clusters that were to be used at the start of a word.
On a grammatical point of view, he said that it became easier when he was able to determine what he was permitted to do and what he could expand and still remain accurate according to the books.
What he was able to create was a language that was head-initial and lightly inflectional, which is not far from Russian although the vocabulary is closer to that used by the Mongolians during the Genghis Khan era, which in the book were the historical relatives of the Dothraki.
The first time that Dothraki language was introduced was during the first season of Game of Thrones, in the episode where the Dothraki ruler, Drogo, was introduced to Daenerys Targaryen. Drogo was greeted in Dothraki by Illyrio Mopatis. More constructed languages (conglang) were used throughout the show’s several seasons. In the history of TV shows, the Game of Thrones is the only show that features the most number of “conglang” material, which, aside from Dothraki also had Low Valyrian and High Valyrian languages.
He took the patterns of the words created by George R.R. Martin when constructing the new vocabulary, using three distinct combinations: consonant-vowel-consonant, consonant-consonant-vowel-consonant and consonant-vowel-consonant-vowel. Peterson said that he ignored the meanings of the 56 words he found in the three books and initially studied the syllables. He was able to identify that in Dothraki, adjectives and other modifiers come after nouns, prepositions precede nouns and objects follow verbs.
Proudly recalling the very first Dothraki sentence that was said on screen, he said that in the greeting given to Drago, “Athchomar chomakaan, khal vezhven!” that translates to “Respect to one that is respectful, great king” only the word “khal” was from Martin and the rest was from him.