Vas menjar amanida o sopa ahir?

Because Catalan has a very common past tense built with the present tense of anar + an infinitive.

So:

• vas = you go when it stands on its own
• vas menjar = you ate / did you eat

This is called the periphrastic past. It is one of the normal ways Catalan talks about completed past actions.

So in this sentence, vas is not the main verb to go. It is helping form the past tense of menjar.

Both forms are possible in Catalan, but they do not always sound the same.

• vas menjar is the usual way to talk about a completed action in the past, especially with a finished time expression like ahir (yesterday).
• has menjat is the present perfect, which often feels more connected to the present or to a more recent time frame.

Since ahir is a closed, finished time period, vas menjar is the most natural choice in standard Catalan.

Catalan often leaves out subject pronouns because the verb form already shows the subject.

Here, vas clearly shows you singular informal, so tu is not necessary.

You could say:

Tu vas menjar amanida o sopa ahir?

But normally Catalan prefers to omit tu unless you want emphasis, contrast, or extra clarity.

In Catalan, after verbs like menjar, it is very common to leave out the article when talking about food in a general, indefinite way.

So:

• menjar amanida o sopa = eat salad or soup
• menjar una amanida o una sopa = eat a salad or a soup

Adding una would make the items sound more individually counted and a bit more specific. Without the article, the sentence sounds very natural and general.

Yes. Catalan word order is flexible, especially with time expressions.

These are all possible:

• Vas menjar amanida o sopa ahir?
• Ahir vas menjar amanida o sopa?

The version with ahir at the end is very natural and neutral. Putting ahir at the beginning gives it a little more emphasis.

Yes. Vas menjar is you singular informal, used with tu.

Other versions would be:

• Vostè va menjar amanida o sopa ahir? = formal singular
• Vau menjar amanida o sopa ahir? = informal plural
• Vostès van menjar amanida o sopa ahir? = formal plural

Catalan changes the verb form depending on who is being addressed.

Yes, in this sentence o simply means or.

It offers a choice between two possibilities:

• amanida
• sopa

Like English or, it does not always have to be strictly exclusive in a logical sense. In everyday speech, it usually just presents alternatives.

Catalan uses question marks like English: normally just one at the end.

So:

Vas menjar amanida o sopa ahir?

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

No. The h in Catalan is silent.

So ahir is pronounced without an h sound at the beginning.

That is true for Catalan h in general: it is normally not pronounced.

Grammatically, you could mix article and no article, but it usually sounds more natural to keep them parallel.

So these feel better:

• Vas menjar amanida o sopa ahir?
• Vas menjar una amanida o una sopa ahir?

Using the same structure for both nouns makes the sentence sound smoother and more balanced.