"The little boy drinks juice."
Translation:Cậu bé uống nước ép.
"Nguoi" means "person" so literal meaning of "nguoi dan ong" means "male person". Normally, you won't hear anyone refer to a child with "nguoi". So it's just "cậu" to indicate male gender or man and "bé" for little. You could think that cậu bé also means little man for fun.
That might be the equivalent of calling someone a "little boy person" or a "male child person"... it just sounds weird, but one would understand you.
It's odd but "người đàn ông" is normal. One might translate that to literally be a "man person"; that sounds weird too. But then maybe "đàn ông" here is understood as the adjective "male"... a "male person" sounds ok..
saying "nguoi" and "cau" together is redundant, which is why you wouldn't hear Vietnamese people saying "nguoi cau be". This just shows that whoever says this, doesn't fully understand how to use/speak the language. (Not talking about people who are learning Vietnamese, I'm talking about people of Vietnamese origin who claims to fluently speak Vietnamese)
The following explains the classifiers, but "bé trai" and "cậu bé" do not require another classifer for "little boy". "câu con trai" means "lad" or not so little boy. https://www.duolingo.com/comment/17166436
" Cậu ‘lad’; a classifier reflecting the attitude of a senior talking to or about a junior: cậu học trò ‘a grade student’ cậu con trai ‘a lad’ cậu bé ‘a little lad’ cậu bán báo ‘a paper boy’ cậu ấm ‘a mandarin’s son’; " http://tinhhoavietnam.net/special/pphap/PParticles/LoaiTu.pdf
I guess this kind of answers my question about the difference in nuance: