It would depend entirely on context. That goes for both the Swedish and the English sentence.
Either of your suggestions seem plausible.
Would DL accept "cosmopolitan" as well for "international" as an adjective to describe someone?
Hmmm....but I would get the sense that this person in this sentence has been well-traveled and worldly. Is that what you're going for? I'm not trying to argue for points, but don't think I've ever heard anyone be described as simply "international" before.
It's a vague sentence, but as a native speaker I would interpret it as that he/she travels a lot or has an "international" job or something similar.
Yes, there's no difference in meaning between mycket and väldigt (when used before an adjective like here)
I don't know if I'm hearing it correctly. Is it roughly pronounced in-ter-nah-twuhn-el? Sorry for the crappy transliteration, I don't know the IPA or any other phonetic alphabet.
Yes, it is pronounced [ɪn.tæ.ɳat.ɧʊ.ˈnɛl]
ɧ is the "SJ sound" and it sounds a bit like WH. It often appears in the same place as English "SH" in cognate words: ship vs skäpp, national vs nationell, shirt vs skjorta, etc etc
The TTL voice seems to pronounce it "internatonel". I thought the second T, as part of the tion suffix, would not be a hard T... Am I wrong? Are there different ways to pronounce it in different regions, like the sj sound?
The TTS pronounces it "internatt-sjonell", and that is correct (at least from what I've heard on Swedish TV). There is both a "t" and a "sj" sound in there. I think it's an exception. And the "sj" part of it can vary, it can sound like "hw" or "sh", depending on the speaker's dialect.
In Swedish just about any time you see a tion you get a kind of "soft t" pronunciation
what is the difference between using mycket, väldigt, and jatte-? I think I saw somewhere else that jatte- was more informal, but us there an official distinction?
There's no difference in meaning between mycket and väldigt when used before an adjective like here.
You can also use mycket to mean a lot, like in mycket pengar = a lot of money and you can't do that with väldigt which only means 'very'.
jätte- is indeed very informal. It would sound a bit odd to combine it with internationell here.