"The man wants a coffee."
Translation:Ο άντρας θέλει ένα καφέ.
Because it's the object of the wanting, so it's in the accusative case.
Nominative (e.g. for the subject of a verb) is ο καφές, ένας καφές but accusative (e.g. for the object of a verb) is τον καφέ, έναν καφέ.
That would be even better -- έναν is supposed to always be written with the final nu in the masculine accusative.
So, just to be sure, the neuter accusative ένα is correct as well as the masculine accusative έναν; I thought coffee was masculine.
I'm not sure I understand your question but I'll try. In Gr. if you had Ο άντρας θέλει καφέ it would mean he wanted coffee, not tea, not orange juice etc. With "ένα" he wants a 'cup of coffee" .
Actually, the indirect article ενα or μια is used much less in Greek than in English. So, whereas in Eng. we would say: "He is a teacher." In Gr. the normal would be: "Αυτός είναι δάσκαλος." You would use "ενα/μια" for emphasis.
(On the other hand, in Greek you use the definite article much more than you do in English. But that's for another time.)
Thanks a lot for your explanation and comments! The comment on Greek using the definite article more was very helpful, because I realised I had thought the need for the definite article applied also to the case at hand.
I want = (Εγώ) θέλω
You want (singular) = (εσύ) θέλεις
He/she/it = αυτός/αυτή/αυτό θέλει
we want = (εμείς) θέλουμε
you want (plural) = (εσείς) θέλετε
they want = αυτοί/αυτές/αυτά θέλουν(ε).
For this type of verb the simple present endings are -ω, -εις, -ει, -ουμε, -ετε, -ουν(ε).
Was this on the web or Android and what kind of exercise was it? Was it a Gr to Eng, or a Strengthen skill, or choose the right answer etc? It will be a great help to know this so we can correct the error.
I've been asking myself from the beginning when to use kafe respectively kafes.