brilliant, thank you. The street I live in in Vung Tau is called Ha Long...which I think means "descending dragon"....there's these brilliant big dragon shaped hedges just by my house: https://captainofthebackseat.files.wordpress.com/2016/03/img_2081.jpeg
Then there's the island next to us Long Son...and the next peninsula, Long Hai...DRAGONS EVERYWHERE!!!!!
(classifier con) rồng
Non-Sino-Vietnamese reading of Chinese 龍 (“dragon”; SV: long), from Middle Vietnamese ròu᷄, from Proto-Vietic *roːŋʔ
đậu rồng (“winged bean”)
vòi rồng (“tornado”)
It seems you could ask ten different Vietnamese people and get ten different answers. I'm going with this is a mistake and it should either be pronounced Zong in the Northern accent or Rong in the southern. Having said that I speak via skype to two different Vietnamese guys, both from the Hà Nội and one says Rong with a rolling R and the other says Zong. Time to move on to the next confusing word.
There are many ways to pronounce RỒNG:
Rồng (as in Spanish rolling r: Rojo, Rico);
GIồng (as in English z: Zoo, haZard);
Rồng (I don't know the IPA symbol for it, but this R sounds like R in Mandarin Chinese: 日 rì, 热 rè);
Rồng (as in English ʒ: PleaSure, televiSion);
Gồng (as in English g: Game; Go);
Dồng (as in English j: You, Yes);
and some other varieties. :(
You just need to stick to the one you are most comfortable with.
Thanks for the answer but I still say it's a mistake, in the context of it's a mistake to use any other pronunciation other than the Northern/Hà Nội or Southern/HCMC accent. I mean if the whole Vietnamese course was to include more than the two main accents it would be just plain ridiculous. Learning Vietnamese is difficult enough no need to make it harder than it needs to be by adding in regional pronunciation variations.