Say or Tell ?
Your choice!
Say
Exemple : ‘’Please don't say that!’’
The verbs "say" and "tell" are commonly mixed up with each other. "Say" is most commonly used in direct speech and does not need an object. The verb "say" is used when what was said is of greater importance than the person to whom it was said.
Tell
Exemple : ‘’Please tell me if you are going to be late.’’
The verb "tell" needs an object as with this verb the person to whom something is said is of greater importance than the information itself.