Què suposes?

Because què is an interrogative word here, meaning what?

The accent helps distinguish it from que, which usually means that, which, or introduces a clause.

• Què suposes? = What do you suppose?
• Suposo que sí. = I suppose that yes / I suppose so.

In questions, què often keeps the accent when it stands on its own or introduces a question.

Catalan does not use a helper verb like English do in this kind of question.

English:

• What do you suppose?

Catalan:

• Què suposes?

The verb suposes already carries the meaning you suppose, so no extra word is needed.

Suposes is the 2nd person singular present tense of suposar.

So:

• jo suposo = I suppose
• tu suposes = you suppose
• ell/ella suposa = he/she supposes

In Què suposes?, the subject is you singular, informal.

Because Catalan often omits subject pronouns when they are already clear from the verb ending.

• suposes already tells you it means you suppose
• so tu is optional

You can say:

• Què suposes?
• Tu què suposes?

Both are possible, but the version without tu is very normal and natural. Adding tu can give extra emphasis, contrast, or clarity.

Yes. Què suposes? uses the informal singular form, like speaking to one person you would call tu.

A formal singular version would be:

• Què suposa?

That goes with vostè.

If speaking to more than one person, you could say:

• Què suposeu?

A rough pronunciation is:

• keh soo-PO-zes?

A more Catalan-like pronunciation, especially in Central Catalan, is approximately:

• [ˈkɛ suˈpɔ.zəs]

A few useful points:

• què sounds like keh, with an open e
• s between vowels in suposes sounds like z
• the stress falls on -po-: su-PO-ses

Pronunciation can vary a bit by region.

Normally, the natural order is:

• Què suposes?

Putting què first is the standard way to ask what do you suppose?

Suposes què? is generally not the normal neutral version. It could sound marked, surprised, or like an echo question, depending on context.

You may also hear:

• Tu què suposes?

That is still normal, with extra emphasis on you.

This is a very common learner question.

• què = what?
• que = often that, which, or a connector

Compare:

• Què suposes? = What do you suppose?
• Suposo que vindrà. = I suppose that he/she will come.

So in your sentence, it must be què, because it is asking what.

Yes, it is grammatical and natural, but the exact tone depends a lot on context and voice.

It can be:

• a genuine question: What do you suppose?
• a slightly challenging question: What are you assuming?
• a rhetorical question, depending on tone

In everyday speech, people might also use nearby expressions such as:

• Què creus? = What do you think?
• Què et penses? = What do you think? / What are you imagining?

So Què suposes? is fine, but its nuance can feel a bit more like what are you assuming/supposing?

A very natural way is to start with Suposo que... = I suppose that...

For example:

• Suposo que vindrà. = I suppose he/she will come.
• Suposo que tens raó. = I suppose you’re right.
• No ho sé; suposo que sí. = I don’t know; I suppose so.

This is useful because it shows how suposar works in both a question and an answer.

No. In standard Catalan, you normally just use the final question mark, like in English:

• Què suposes?

Unlike Spanish, Catalan does not normally use an opening inverted question mark ¿.