Hi R-J,

Here's a transliteration of the lyrics and a rough English translation (almost word for word, to show what the individual words mean) : as I said before, Вьюн (vyon) can mean many things: loach (fish), eel, and by extension a slippery person/character: it also means a fidget/fidgety person, and is a popular name for a dog!: and apparently it's also a dialect term for fog or mist - this is suggested by this video, which illustrates the story as it develops: https://www.youtube.com/watch?v=UCo3yjouhi8

Some commentators suggest, as I said earlier, that Вьюн can mean weeds/bindweed (as you suggested), and hence by extension is a variant of the word for a wreath or headdress made from the weeds - as in the video by the Slavic Ensemble. So you pays your money and you takes your choice!

Some versions (as in the video above) end with the groom accepting his bride, but others have him rejecting her too, and taking a staff and scrip (bag) because he is "betrothed to God" - presumably becoming a monk or a pilgrim/beggar. I've included all the verses, but you could miss out the last one if you want a happy ending!

Cheers,
John
Vyon nad vadoi, oi, vyon nad vadoi Mist on the water, oh, mist on the water
Vyon nad vadoi rassteelayetsuh. Mist on the water spreads out
Zheneek oo varot, oi, zheneek oo varot, The bridegroom at the gate, oh, the bridegroom             at the gate
Zheneek oo varot dazheedayetsuh The bridegroom at the gate is waiting

Veevyelee yemoo, oi, Veevyelee yemoo, They brought him, oh, they brought him
Veevyelee yemoo voronovo konya.         They brought him a black horse   
- Eta nye mayoh, oi, eta nye mayoh       This is not mine, oh, this is not mine,
Eta nye mayoh, eta batyushki movo         This is my father's.

Vyon nad vadoi, oi, vyon nad vadoi Mist on the water, oh, mist on the water
Vyon nad vadoi rassteelayetsuh. Mist on the water spreads out
Zheneek oo varot, oi, zheneek oo varot, The bridegroom at the gate, oh, the bridegroom             at the gate
Zheneek oo varot dazheedayetsuh The bridegroom at the gate is waiting


Veenyeslee yemoo, oi, Veenyeslee yemoo, They brought him, oh, they brought him
Veevyelee yemoo soondookoo, polnee dabra They brought him a chest full of treasure
- Eta nye mayoh, oi, eta nye mayoh       This is not mine, oh, this is not mine,
Eta nye mayoh, eta dyevyera movo.         This is not mine, it's my brother-in-law's

Vyon nad vadoi, oi, vyon nad vadoi Mist on the water, oh, mist on the water
Vyon nad vadoi rassteelayetsuh. Mist on the water spreads out
Zheneek oo varot, oi, zheneek oo varot, The bridegroom at the gate, oh, the bridegroom             at the gate
Zheneek oo varot dazheedayetsuh The bridegroom at the gate is waiting

Veenyeslee yemoo, oi, Veenyeslee yemoo, They brought him, oh, they brought him
Veenyeslee yemoo svyet-Nastasyushkoo.    They brought him his darling Anastasia
- Eta vot moyo, oi, eto vot mayo,                This is mine, oh, this is mine,
Eta vot mayo, bogom suzhenoye                This is mine, betrothed by God


The alternative ending:

Veenyeslee yemoo, oi, Veenyeslee yemoo, They brought him, oh, they brought him
Veevyelee yemoo svyet-Nastasyushkoo.    They brought him his darling Anastasia
Eta nye mayoh, oi, eta nye mayoh               This is not mine, oh, this is not mine,
Eta nye mayoh, eta druga movo                   This is not mine, it's my friend's

Veenyeslee yemoo, oi, Veenyeslee yemoo, They brought him, oh, they brought him
Veevyelee yemoo pasok ee soomoo            They brought him a staff and a scrip
- Eta vot moyo, oi, eto vot mayo,                This is mine, oh, this is mine,
Eta vot mayo, bogom suzhenoye                This is mine, betrothed by God