Sortir vs. partir vs. s'en aller

The French verbs 'sortir', 'partir', and 's'en aller' are often used interchangeably by non-native speakers because they can all mean 'to leave' or 'to go out'. However, they convey different nuances and are used in specific contexts. Understanding these differences can greatly improve one's ability to express departure or movement in French.

Sortir

'Sortir' typically means 'to go out' or 'to exit' from a place such as a building, vehicle, or room. It can imply going out for social, leisure activities, or simply to leave indoors.
Je sors prendre l'air.
(I'm going out to get some fresh air.)
Tu sors ce soir ?
(Are you going out tonight?)
Il est sorti de la maison précipitamment.
(He left the house hastily.)

Partir

'Partir' is used to indicate leaving a location with the intention of starting a journey or moving towards a different destination. It can also convey the idea of departure without an immediate return in mind.
Nous partons en vacances demain.
(We're leaving for vacation tomorrow.)
Il est parti tôt ce matin pour éviter la circulation.
(He left early this morning to avoid traffic.)
Elle part pour New York la semaine prochaine.
(She is leaving for New York next week.)

S'en aller

This reflexive form of 'aller' means 'to go away', and implies leaving a place often with a sense of finality or without specifying a destination. It has a slightly more formal or literary tone than 'sortir' or 'partir'.
Il est temps que je m'en aille.
(It's time for me to go away.)
Elle s'en est allée sans dire au revoir.
(She went away without saying goodbye.)
Après la réunion, tout le monde s'en est allé discrètement.
(After the meeting, everyone left discreetly.)

Summary

While all three verbs share the concept of leaving, each has its own nuances in practice; 'sortir' often involves leaving buildings and short-term trips, 'partir' implies leaving for a trip or moving to another place, and 's'en aller' usually carries the idea of leaving, possibly without returning soon, with more emphasis on the act of leaving itself rather than the destination. Recognizing these subtleties can make one's French more accurate and expressive when talking about departures or exits from places or situations.