it's like "shoon" as in like spoon, but with a slight opening of the vowel at the end, it's written "schoene" and uses the old latin OE which is encoded with the umlaut (two dots above a vowel) which in most cases means the vowel is opened out to an E sound before the next consonant, it's not a or u or e it's something in between... in hungarian and turkish and chinese there is 25 vowels, they have a vowel for every combination, oe, au, ui, ia, iu, etc etc, you can imagine the grid of aeiou and then left is first top is second, it is hard for most people who don't speak these languages to catch the extra vowels

like, bulgarian only has 6 vowels, one being this funny "uh" called "er maluk" and then a number of dipthongs, mostly "ey" (like how we say a in english) and "ay" which is like how we say I, and their "i" is like "ee"

i think the best way to visualise it is the grid of paired vowels though, and you can put a dot in there to represent every vowel or vowel/semivowel pairing

oh yeah and then there is rules about those hidden pauses... bulgarians have weird ones about that, they "devoice" the consonants with voice, and it makes their speech sound like a machine gun going off lol, PRRRRRRRTTTT lol