Questions & Answers about Eu disse tchau.
Disse is the first-person singular preterite form of dizer, which means to say.
So:
- dizer = to say
- eu disse = I said
This is an irregular verb, so you cannot guess disse just by taking the infinitive and adding a regular ending.
Disse is in the pretérito perfeito (the simple past / preterite).
It refers to a completed action in the past:
- Eu disse tchau. = I said bye.
It does not mean I was saying bye. For that kind of ongoing past idea, Portuguese would use a different structure.