The key rule

VerbPatternExample
SAY say + something
say + to someone + something
She said "hello".
He said to me that he was tired.
TELL tell + someone + something
tell + someone + to do sth
She told me her name.
He told us to be quiet.
Key difference: Tell needs a person right after it: "tell me, tell her, tell John". Say does NOT need a person directly after it: ✓ "She said hello" ✗ "She said me hello".
Common mistakes:
✗ "He told that he was sick." → ✓ "He said that he was sick."
✗ "She said me to go." → ✓ "She told me to go."

Fixed expressions

With SAYWith TELL
say hello / goodbyetell the truth
say sorrytell a lie
say please / thank youtell a story / joke
say a word / somethingtell someone the time
say yes / notell someone your name
say a prayertell the difference

Exercises

Say or tell? Choose the correct form.

1. She ___ me that the film was great.

2. "Goodbye!" he ___ and left.

3. Always ___ the truth.

4. The teacher ___ that the test was on Friday.