"I am not a man."
Translation:Tôi không phải là một người đàn ông.
Why wouldn't "Tôi không phải là một đàn ông" be acceptable? In this context, I'm not counting a noun, at least I think with regard to using một in this way. For context I was using it as "a" instead of "one". Or should I, when in doubt, add a classifier just to be safe?
In Vietnamese, whenever a number appears before a noun, you must use the classifier for that noun. Note that Vietnamese doesn't have articles. Một is not an article. It just have the same meaning (not function) as a.
Correct me if i'm wrong but I think the locals tend to drop the 'là một người' and just say 'tôi không phải đàn ông', hence keeping it short and simple. Of course only do this outside Duolingo since Duolingo wants to teach you the correct and proper way of speaking Vietnamese.