One of the joys of fantasy novels and TV series is the world building that comes along with them. The meticulously crafted history and detail is a key component to the popularity of series like Harry Potter or Lord of the Rings. George RR Martin's A Song of Ice & Fire is no different. It is a fully realized world, with cultures and languages to match. However, language can be tricky, especially with mispronunciations. For instance, how to pronounce "Khaleesi" has turned out to be very different than most people assumed.
Misunderstanding how words are supposed to be pronounced orally is not an issue limited to fantasy languages. Anyone who reads a lot can wind up with a written vocabulary they don't know how to pronounce. For instance, when I was 13, I was shocked to learn the word "segue" which I had believed to be a synonym for "segway," was the word itself. In college, a boyfriend of mine said I looked "eth-err-al," I gently corrected him the word was pronounced "ee-thee-ree-al." (I recognized it instantly, having made the same mistake when reading the word "ethereal.")
This happens more often in fantasy stories since these are not words used in everyday language. A name like "Sansa" is easy, but what about "Daenerys"? (Daan-are-ees? Dee-nair-ess?) That's where David Peterson, the linguist for shows like Game of Thrones comes in.
Peterson invented the Dothraki language based on the words Martin used on the page. When Drogo and his people speak, they're not just babbling. Peterson created an entire language with verbs, conjugation, future perfect, past participles, and all that good stuff. For most of it, his pronunciations of things were the law. But when it came to the word "Khaleesi," a title which is used a lot in the novels, Peterson's interpretation failed to stick.
Peterson recently ranted about how the word should be pronounced during his appearance on The Allusionist podcast. It comes around the 18-minute mark.
Peterson looked at the word and saw not a three-syllable word of "Kaa-Lee-See," but a four-syllable word.
So I had to decide am I going to re-spell this thing because I know how people are going to pronounce this, or am I going to honour that spelling and pronounce it differently? I made the latter decision and I think it was the wrong decision... Changing the spelling to K-H-A-L-I-S-I' would have fixed all my problems. 'EE' and 'I' can't be pronounced the same because they're spelled differently.
Peterson looked at the word and saw "kh," which, in Hebrew, is pronounced with a guttural soft "cha." Most Americans will recognize it as being "as in Chanukah." Once that becomes the first syllable, the rest of the word flows from it, making it Kha-Leigh-eh-See. Written phonetically: "Ha-Lay-Es-Sea," which a guttural sound on the "h."
To be clear, I understand why the show says "KAL-Lee-See." As an American reading the book whose first language is the Germanic-and-Anglo Saxon derived language known as English, that was my internal pronunciation too. However, having heard Peterson's version, I wish he'd won out.