"She has beautiful black eyes."
Translation:Elle a de beaux yeux noirs.
"j'ai les yeux bleus" is the French way to simply say "I have blue eyes" OR "mes yeux sont bleus / my eyes are blue".
- "elle a les yeux noirs" (= she has black eyes) gives the same type of descriptive information
- "elle a de beaux yeux noirs" (= she has beautiful black eyes) gives a subjective qualification about these black eyes.
This changes the grammatical structure (in both languages) with:
- "beautiful black eyes" as the plural of "a/one beautiful black eye"
- "de beaux yeux noirs" as the plural of "un bel oeil noir"
- elle a un oeil noir (she has a black eye) = one
- elle a des yeux noirs (she has black eyes) = more than one (2 in this case)
Remember: indefinite article "un/une" has a plural form: "des", whereas the English a/an has none.
In addition, "des" becomes "de" in front of an adjective:
- elle a des yeux noirs -> elle a de beaux yeux
This is very worrying, unless you are now describing animals. Humans can have dark eyes, dark brown eyes. Black is not biologically possible without rare disease. Worse, in English a black eyes(s) normally refers to injury of the whole eye area. Ordinarily, we would think of being struck by another person (violence) as a likely cause. You mean Beautiful dark eyes, surely, Duo! Or the dog?!
I'm not doubting the French, more the English. The only time we would use "black eye" in the UK is a bruising in the eye usually caused by an attacker. In the UK, if we're complementing eye colour, we use "dark eyes." I understand that there may be regional variation but as someone who has worked with victims of domestic violence in the past, to call it a black eye in English is seriously disturbing.
You know, I think a native speaker would actually be able to make a distinction between the two meanings, but it would be subtle. If I intended to praise her very dark eyes, I would leave a very slight pause between "black" and "eyes"; in making a remark praising her bruises (perhaps she gained them in some honourable way, saving a life?), the two words would run together, as if it were "blackeyes". Ha. In any case, in real life there would be context, which would help immensely.
<Grin> It further occurs to me that when referring to ocular bruises, we would be very likely to emphasize that it was both eyes, since a black eye (bruise) is most often only on one side. So I'd likely say she has two beautiful "blackeyes", whereas this emphasis would be entirely unnecessary in the other case.
"Elle a les cheveux noirs" perfectly translates "she has black hair".
Elle a de beaux cheveux noirs = she has beautiful black hair (addition of a Beauty adjective in front of the noun)
Elle a les beaux cheveux noirs de sa mère = she has her mother's beautiful black hair (addition of a possessive = lit. the beautiful hair of her mother).