En parlant, il sourit.
While speaking, he smiles.
Tense guide
Gerund
Use en + present participle to show while doing, by doing, or through doing another action.
When to use it
It connects two actions with the same subject: Elle apprend en écoutant means she learns by listening.
How to recognise it
It always has en before an -ant form: en parlant, en finissant, en prenant.
How to form it
Use en plus the present participle: en parlant, en finissant, en prenant.
A simple rule
The gerund usually shares the subject of the main verb. Avoid it if the two actions have different subjects.
Examples
Elle apprend en écoutant.
She learns by listening.