Eu disse obrigado.

Yes, you often can leave it out in Portuguese.

Portuguese usually allows the subject pronoun to be omitted when the verb form already makes the subject clear. Since disse means I said, eu is not strictly necessary.

• Eu disse obrigado. = I said thank you.
• Disse obrigado. = also I said thank you.

Including eu can add emphasis, contrast, or clarity.

Disse is the past tense form of the verb dizer, which means to say or sometimes to tell.

Here, disse means:

• I said

So:

• Eu disse obrigado. = I said thank you.

This is the preterite form, used for a completed action in the past.

Because dizer is the infinitive, meaning to say, while disse is the conjugated form meaning I said.

Compare:

• dizer = to say
• eu digo = I say
• eu disse = I said

So the sentence needs the form that matches I and the past meaning, which is disse.

Yes. Obrigado/obrigada changes according to the gender of the person speaking, not the person being addressed.

• A man usually says obrigado
• A woman usually says obrigada

So:

• If a male speaker says it: Eu disse obrigado.
• If a female speaker says it: Eu disse obrigada.

This is one of the most common questions learners have, because in English thank you never changes, but in Portuguese it can.

Yes, in everyday use obrigado (or obrigada) means thank you.

Literally, the word has a historical sense related to being obliged or grateful, but for learners it is best understood as the normal way to say thank you.

In this sentence, disse obrigado means said “thank you.”

No. You do not use que here.

Portuguese can put the reported words directly after disse:

• Eu disse obrigado.

You could also say:

• Eu disse “obrigado”.

But que is not needed before a single expression like obrigado.

Yes, it is understandable and natural enough, especially in narration:

• Eu disse obrigado e fui embora. = I said thank you and left.

That said, in everyday Brazilian Portuguese, people may also express the same idea in other ways, such as:

• Eu agradeci. = I thanked him/her/them.
• Eu falei “obrigado”. = I said “thank you”.

So Eu disse obrigado is correct, but it is not the only natural way to say this.

Both can often be translated as I said, but they are used a little differently.

• disse comes from dizer and often focuses on what was said
• falei comes from falar and often relates more generally to speaking

With a direct expression like obrigado, both can work:

• Eu disse obrigado.
• Eu falei obrigado.

Many Brazilians may prefer falei “obrigado” in casual speech, but disse obrigado is still fine.

Yes.

You can write:

• Eu disse “obrigado”.

This makes it very clear that obrigado is the exact word that was spoken. Without quotation marks, the sentence is still correct and commonly understood.

In standard Brazilian pronunciation, disse sounds roughly like JEE-see or DJEE-see, depending on accent.

A rough breakdown:

• di- often sounds like jee or djee in many parts of Brazil
• -sse sounds like see

So disse is approximately:

• JEE-see

This is only an approximation using English sounds, but it helps many beginners.

Absolutely. In real life, people usually just say:

• Obrigado!
• Obrigada!

The full sentence Eu disse obrigado is only used when you are talking about the act of thanking, not when you are actually thanking someone.

So:

• Speaking to someone directly: Obrigado!
• Telling a story: Eu disse obrigado.

The normal order is:

• Eu disse obrigado.

Portuguese word order is somewhat flexible, but Obrigado eu disse would sound unusual in ordinary speech and would only work in a very marked or dramatic context.

For a learner, the safest order is:

• Eu disse obrigado.