Je suis & Je suis un

[yong leong]

would somone be kind enough to point out to me the difference between saying "Je suis un professor" and "Je suis professor", normally when you say you are a doctor or a nurse you just say "je suis medicine" or Je suis infirmier" what happen when you made a mistake and say "Je suis un professor" because it is a direct translation from english " I am a professor".

[Crack1]

When referring to a person's profession or religion, the indefinite is not used in French, although it is used in English.

Je suis professeur.
I am a teacher.

Il va être médecin.
He's going to be a doctor.
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The indefinite article usually refers to an unspecified person or thing.

J'ai trouvé un livre.
I found a book.

Il veut une pomme.
He wants an apple.
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The indefinite article can also refer to just one of something:

Il y a un étudiant dans la salle.
There is one student in the room.

J'ai une sœur.

[ Do remember that French and English have different spelling for the word 'professor'. ]

[yong leong]

Merci beaucoup, Crack1, this is indeed a good forum . Have a nice day.

[Neil Coffey]

Both are potentially possible sentences of French, but there's a subtle difference. If you say 'je suis professeur', you're essentially stating what your job is. If you say 'je suis un professeur', you're talking about your nature/what kind of person you are (cf English "I'm a teacher at heart").

[Adam Kim]

What I learned from learning French is unusual. There are numerous differences between the French and English usages of indefinite articles.