What is happening right now
French has no "-ing" form. With être en train de + infinitive you say that someone is in the middle of an action, like "I am in the middle of eating".
Je suis en train de manger.
I am eating (right now).
Elle est en train de parler au téléphone.
She is on the phone (right now).
Nous sommes en train de travailler.
We are working (right now).
Elision and negation
If the infinitive starts with a vowel or a mute h, de becomes d': en train d'écrire.
Il est en train d'écrire un message.
He is writing a message.
Nous sommes en train d'apprendre le français.
We are learning French (right now).
Only être is negated: ne … pas wraps around the être form, and the rest of the construction follows unchanged.
Je ne suis pas en train de manger.
I am not eating (right now).
Il n'est pas en train de dormir.
He is not sleeping (right now).
Progressive or simple present?
English uses "-ing" almost every time something is happening now. French usually does not: the simple present covers both "I read" and "I am reading", so Je lis is often enough. Use être en train de to stress that it is happening at this very moment, for example when answering "What are you doing?".
Qu'est-ce que tu fais ?
What are you doing?
Je suis en train de cuisiner.
I'm cooking (right now).
Je lis un livre.
I'm reading a book. (also possible)
