Weird. It sounds like một is also being pronounced like mộn too. Might just be hearing things...
This speaker often pronounces 'Một' as 'Một n'
Also, anh and ang do sound similar if you're not used to listening for the difference. nh is articulated further forward in the mouth than ang though, so it has a bit of a higher pitch. It is somewhere in between n and ng. nh is similar to the spanish ñ but just a little bit further back.
English speakers don't differentiate between the sound in king from the sound in kong. The sound he's making here sounds like the ng from king.
I also hear him say mộn instead of một. And this is not the only time I hear him say it that way. It seems to happen most of the times. It's very weird.
Một do sound like mòn haha but yeah xanh sounds normal to me ^_^ anh is like a mix of a nasal vowel like "in" in French and "ng". I believe in the south they pronounce it like a regular "n"
Because the position of your mouth is similar. It is very evident in singing that -t words are elongated to sounding like -n and similarly -c into -p.
Also because the t in "một" doesn't have a plosive ending. So it'll sound more like "mộn" than "một" at times. Just listen carefully and you'll hear the t
The pronunciation things mentioned above are something I only really notice when I hear Northern speakers. When I hear southern speakers I don't notice it much. Feel free to pronounce it either way. I speak with a southern accent but people in the north can understand me just fine
I assume that 'xanh da trời' is the nothern word for 'blue', as my family are from the south and I have always been taught that it is 'xanh nước biển'.
There are different shades of blue. The word xanh by itself is a corruption of 青 (thanh in Sino-Vietnamese) and carries the general meaning of blue-green (since the two colours were historically seen as just different shades of the same).
Xanh da trời = sky blue
Xanh biển/dương = sea/navy blue (dương is more of sea/ocean blue)
Xanh lá (cây) = green
Then you also have xanh lục and xanh lam which can be used to distinguish between a generic green and blue.
A blue rabbit is more exact as well as more natural sounding. I would say your version is not exactly correct. In the appropriate context it might be accepted but by itself I'd say no