So the voice acting of the show is ... inaccurate?
I went to Youtube to hear some spoken Valyrian from the show.
There is a particuliar scene where Danaerys says "Dracarys" to a dragon.
She does not say "Dracarys"! She says "Drakaris". "y" is supposed to sound like y. (By the way, why is there a "c"? I can find this letter in the alphabet of the first lesson.)
I must admit that I have never watched the show, but I wonder if learning the language in Duolingo would make me enjoy it less, because of imperfections in pronunciation.
If you watch this very amusing interview with the creator of the language, David Peterson, you'll see that this happens all the time. https://www.youtube.com/watch?v=E0BupJ3Uow0t=31sindex=2list=FLCilKP1XwUM7M7GhB3fFF_w
He's not actually on set, but pre-records the lines for the actors. Since High Valyrian is a made-up language, and the vast majority of people watching Game of Thrones don't know it, and don't care how it is pronounced :)
I think in Firefly it partially has to do with the state of the characters. They are rebels that don't like the big galactic organization - whose base language is Chinese - so it's a very small form of rebellion to intentionally butcher it. Obviously the characters would know how things are supposed to sound, but my guess is maybe they choose to mispronounce it as a subtle but verbal "f* you"?
No, that makes no sense. Everyone is English-Chinese bilingual. Chinese is not the language of their oppressors. A better in-universe explanation would be that it's the future and the language has evolved over time, as it does. English has also changed, but per convention it's "translated" into the English we speak today, with only a handful of words and phrases (like "shiny") for flavor.
The actors are mostly basing their pronunciations on English (understandably) in which the y vowel simply is not a thing. It's not really surprising that they'd get it (among other things, like q) wrong.
As far as I can hear, btw, Danaerys's pronunciation of y is maybe a bit more central than the usual i, so at least there's some differentiation going on.
Phonetics+phonology 101: Never base pronunciation on orthography. The Valyrian words you see in DuoLingo don't necessarily represent phones. Not sure if there are any actual resources for the phonetic inventory and phonological variation of the language, but you could even put it down to accents if you wanted! I mean, Valyrian is pretty much the lingua franca of Essos, right? That's a lot of people, and a lot of opportunity for dialectal differences!
The spelling is relatively phonetic, but if you were to have an orthography with 100% correspondence to the pronunciation it would be extremely complicated and not terribly conducive to efficient language learning. Much the same as, say, Italian. Spelling is pretty representative of pronunciation, but finer details need to be learned by ear. (:
David Peterson, the creator of the language, doesn't actually get to work with the actors on the language and pronunciation. He records the pronunciation and it's up to the actors how close they get. Given that English is a primary language, if not the native language, for (I think) all of them it makes sense that some sounds that are not in English aren't maintained without being extra careful, which they aren't, given all the other things they have going on in a scene.
fun fact: strictly (linguistically) speaking, an [y] is only an umlaut if it used to be a [u] that assimilated to a following speech sound, thus becoming a distinct speech sound itself.
Maybe you know this, because you correctly wrote "what in German is", since that wouldn't make "y" an umlaut. Still "y" is not an umlaut in German, even by a non-strict non-linguistic definition (because the letter is neither an umlaut character like ü nor an umlaut by the definition above).
If, following linguistic conventions, you put it in brackets or slashes you can correctly state that [y] is a pronunciation of the Umlaut /y/ in German.