I have a question about 위
I why is it when 우 is by itself its [u] but when you add ㅣto it becomes 위 [wi] Why does the sound for ㅜ become [w] and not [ui] ?
I'm Korean, and I tested some Korean lessons here. There are critical discord in actual Korean pronunciations and phonics characters represented here. Especially 어, 여, 으, 의 kind of things are very different from [eo, yeo, eu, ui] sound. Here is actual 의 sound lesson. https://youtu.be/qTya2TDIYDQ?t=40 For me, [wi] and [ui] are same sound, so you can say 위 is [ui] = 우[u] + 이[i] . 으 sound + 이 sound = 의 sound in Korean exactly, so King Sejong was not wrong, haha. 으 is not [eu] sound, so [eu] + [i] doesn't make [ui] sound, too. In short, 위=[wi, ui], 의≠[ui].
ui sounds very similar to wi, in fact if you say it really fast it sounds like wi. I don't know what King Sejong was thinking but I guess it made sense to him.
The vowels "u" and "i" are closed vowels (lips and tongue respectively). Close a little further and they become "w" and "y" consonants. Happens with diphthongs in a lot of languages (like how the "ua" in language sounds like "wa").