French language Q&A Forum

I was wondering why the use of indefinite articles with descriptive nouns was no longer in use. For example, I learned to say "Je suis une chanteuse." But, a textbook I am using in my class simply says "Je suis chanteuse." First, why is the un or une no longer included and second, is it grammatically correct to say something like "Je suis fille." or "Il est homme."? Much appreciated for any help. Rules have changed since I was a student.