What if I would want to say : Your sibling IS drinking wine? Would it be the same Polish sentence?
It is accepted here, although such an interpretation is unusual. At least in Polish, if it's one sibling, you'd just specify whether it's a brother or a sister.
How sg does rodzeństwo behave ? It takes a sg verbform apparently but possessive pronoun. Twoje... How about adjectives, pl or sg ?
There are no surprises, if it's singular, then it takes singular forms of everything.
"Rodzeństwo" is neuter, and neuter forms are identical to not masculine-personal plural, so this indeed might be confusing. But it's definitely neuter singular possessives, neuter singular adjectives, etc.
In rodzeństwo, do you pronounce the letters "d z" separately, or together like an english J sound?
Neither - although a lot closer to the second option. There is a number of digraphs in Polish, and the one that makes the English J sound is dż, not dz.
The 'dz' sounds in not a popular one in English, but you can find it sometimes - think of the last sound of the word "woods".
But in English I would never say “your siblings”
I would say “your children” or “your kids”
Yeah, well, those are completely different notions, right? Siblings are brothers and sisters, not children.
It sounds like the stress in rodzeństwo is on the ń. Is it possible? Does ń have an intrinsic [i] sound in its pronunciation?
I guess the ń is a bit overemphasized by TTS, the stress should be like this: rodzEństwo.
Ok. So the ń just sounds like a normal n here? Because it's very hard to imagine the sound s after ń, and it's even harder to pronunce it.
It should sound like an ń. Unfortunately I can't come up with any tips how to pronounce it. Maybe you could listen to some audio recordings on forvo and wiktionary.