what to say
I didn't know what to say.
Personne ne savait vraiment quoi dire.
No one really knew what to say.
Nous ne savions pas quoi dire.
We didn't know what to say.
Le plus dur, c'est de décider quoi dire et quoi taire.
The hardest part is deciding what to say and what to keep quiet.
— Terminator (1984)
Tout à coup, personne ne sait plus quoi dire.
Suddenly, no one knows what to say.
Je te dirai exactement quoi dire.
I'll tell you exactly what to say.