There's no "st" sound or consonant cluster in Korean, or at least no way to write it, so they break it up with a vowel "ㅡ"=="eu".
You also need at least a consonant and vowel I every syllable block, so "s"=="ㅅ" can't be by itself, so you add "ㅡ"=="eu" to complete the syllable block.
Someone please correct me if I'm wrong.
Well, with this particular word it's mainly because /ks/ isn't a valid cluster at the end of a syllable, while it is in English. Hence "Starbucks".
So, to circumvent this issue, Korean adds ㅡ <eu> at the end to break up the cluster across 2 syllables so it can be pronounceable for Koreans.
For the intial cluster, you're spot on regarding that it doesn't exist as a native cluster, so it's modified.
I'm brand new and I agree with you--I'd rather be rid of it already. But when reading the notes, for this section (skill or whatever), based on Samsung and Hyundai, I much prefer the older romanization and I'm puzzled as to why they changed it to something that is (in my opinion) worse.
I feel like the pronunciations on these aren't great, tho I'm not very experienced in Korean at all. The pronunciation at the end here sounds more like an "ih" sound than an "eu" sound. Is that normal?
Also I didn't mention it before but when teaching "야" it sounded more like "yeah" than how I had learned it to sound like, "yah" - I thought "ㅏ" is only supposed to sound like "ah"?
As for your first point, that's pretty normal--"eu" is the standard romanization, but the romanization isn't necessarily anglicization (meaning it's not necessarily how an English speaking person would spell it). In fact, English practically doesn't have the sound.
As for your second point, I'm really unclear on that, too, and will probably utilize outside resources. I thought it was "a" as in "father," not "a" as in "fat," but I could be mistaken, or maybe it depends on the word (just like "a" in English is different in "father" from how it is in "fat").
you're in the reading section, meaning you have learned a few Korean letters and their corresponding soundings. you then need to apply them in these exercises. hovering over the words can be helpful in the first times. Duo's method is based on trial & error, you keep doing it until you master it.
both 아 andㅏhave the [a] sound. while 아 is a complete syllable block and can be on its own, ㅏ, as a sole letter, can't. a complete block needs at least one initial consonant and one vowel. if there is no initial consonant, ㅇ replaces it and 아 is formed.
I hear "Stabuksè" (stabuksay)?
So 스 + 타 = Sta. If I got it?
I read for "star" they transliterat "seutta": 스타 Maybe a trend among Asian not to pronounce the final consonant I think.
If I want to write it "스타르", is it possible?
What's the difference between 북 and벅? I can't hear them on Google Translate.
스타르 would sound like [seu-ta-reu] and not like the English "star". honestly the original 스타 might be closer to "star" than your version.
as a side note, 으 is a [ɯ] sound, a close back unrounded vowel. it is as you're about to say the [u] sound with your lips close, as when you say the [i] sound.
as for 어 vs 우, I would say 어 sound is closer to 오, and 우 to 으.
어 is the [ʌ] sound, an open-mid back unrounded vowel, as in "but", "double".
우 is the [u] sound, a close back rounded vowel, as in "blue", "who".
오 is the [o] sound, a close-mid back rounded vowel, as in "low", "boat".
Not in the English, except possibly in some British and/or Australian accents (I'm from the US so I can't speak to that for sure). The notes for this lesson (or skill or whatever) said that often "r" is left out at the end of a syllable when transliterated into Hangul, since ㄹ is pronounced "l" (not "r") at the end of a syllable, but you can't cluster consonants at the beginning of a syllable (so you can't begin a syllable with ㄹㅂ) to produce the desired effect.