"The little girl wants to eat."
Translation:Bé gái muốn ăn.
No it is not. "Con gái" either means "daughter" (of someone) or is used to identify girls as a whole (in a typical/stereotypical sentence) (e.g. Con gái thích mua sắm - Girls love shopping). "Con gái" should not be used to identify a particular female individual (that's "cô gái").
It takes some practice, but you can get used to it. The discussion here ( https://www.duolingo.com/comment/15390991 ) shows how you can type the Vietnamese characters, and the comments in this discussion ( https://www.duolingo.com/comment/15215426 ) talk about how to pronounce them.
I hope this is helpful.