A la nit em fa mal la panxa i no vull sopar.

A la nit usually means at night or in the evening/nighttime, depending on context.

• a = at / in
• la nit = the night

So A la nit is a time expression meaning something like at night.

It is not usually the same as tonight.
If you specifically want tonight, Catalan often uses aquesta nit.

• A la nit em fa mal la panxa = At night my stomach hurts
• Aquesta nit em fa mal la panxa = Tonight my stomach hurts

Because fer mal is a very common Catalan structure for saying that something hurts.

The pattern is:

[body part] + [indirect object pronoun] + fa mal

or more naturally in standard word order:

Em fa mal la panxa
= My stomach hurts
literally, something like The stomach causes pain to me

Here:

• em = to me
• fa = does / makes
• mal = pain / badly
• la panxa = the belly / stomach

Catalan often uses this kind of structure where English uses my X hurts.

You may also hear:

• Tinc mal de panxa = I have a stomachache
• Em fa mal la panxa = My stomach hurts

Both are possible, but fer mal is extremely common.

Because the verb agrees with the thing that hurts, and here that thing is la panxa, which is singular.

• la panxa = singular
• so the verb is fa = it hurts / it causes pain

Compare:

• Em fa mal la panxa = My stomach hurts
• Em fan mal les cames = My legs hurt

So:

• singular body part → fa mal
• plural body parts → fan mal

Em is a weak pronoun (a clitic pronoun), and here it means to me.

In Em fa mal la panxa, the idea is:

• la panxa is the thing causing pain
• em marks the person affected: to me

So:

• Em fa mal la panxa = My stomach hurts
• Et fa mal el cap = Your head hurts
• Li fan mal els peus = His/Her feet hurt

The pronouns change like this:

• em = to me
• et = to you
• li = to him/her
• ens = to us
• us = to you all
• els / els fa mal or els / els fan mal = to them

Catalan often uses the definite article with body parts, especially when the person is already shown by a pronoun like em.

So instead of saying my stomach, Catalan commonly says:

• em fa mal la panxa
  literally: the stomach hurts to me

This is very natural in Catalan.

Compare:

• Em fa mal el cap = My head hurts
• Em rento les mans = I wash my hands
  literally: I wash myself the hands

So the ownership is understood from em.

Not exactly.

Panxa is a very common everyday word. It can mean:

• belly
• tummy
• sometimes stomach in casual speech

It is more colloquial and physical.

Estómac is more anatomical and specific:

• stomach as the internal organ

So:

• Em fa mal la panxa sounds very natural in everyday speech, especially if someone feels sick or has belly pain.
• Em fa mal l’estómac is also possible, but sounds a bit more specific or medical.

A native speaker might choose either depending on tone and meaning.

Sopar can be both:

1. a verb = to have dinner / to eat dinner
2. a noun = dinner / supper

In no vull sopar, it is a verb, because after vull (I want) Catalan normally uses an infinitive.

• vull sopar = I want to have dinner
• no vull sopar = I don’t want to have dinner

If sopar were a noun, the structure would usually look different, often with an article or another determiner:

• No vull el sopar = I don’t want the dinner / the evening meal
• El sopar és fred = The dinner is cold

So in your sentence, sopar is definitely the verb.

Because Catalan does not use a separate word like English to before the infinitive in this structure.

In English:

• I want to eat
• I want to sleep
• I want to have dinner

In Catalan:

• vull menjar
• vull dormir
• vull sopar

After voler (to want), Catalan directly uses the infinitive, with no extra word.

So:

• No vull sopar = I don’t want to have dinner

Because standard Catalan usually forms negation by putting no directly before the conjugated verb.

So:

• vull sopar = I want to have dinner
• no vull sopar = I don’t want to have dinner

This is the normal pattern:

• No menjo = I don’t eat
• No puc venir = I can’t come
• No vull sopar = I don’t want to have dinner

In some informal speech, especially in some dialects or very casual conversation, no may be omitted in certain contexts, but learners should use no.

Both are possible.

• Em fa mal la panxa is very natural and common.
• La panxa em fa mal is also correct, but it gives more emphasis to la panxa.

Catalan often places the weak pronoun before the verb, and the body part can come after:

• Em fa mal el coll
• Em fan mal les mans

If you move the body part to the front, it sounds more highlighted:

• La panxa em fa mal
• El cap em fa mal

So the original sentence uses the more neutral, very common order.

Yes. All of these are possible, but they are not identical in tone.

• Em fa mal la panxa = everyday, natural, very common
• Em fa mal l’estómac = more specific, a bit more anatomical
• Tinc mal de panxa = I have a stomachache / bellyache, also very common

A learner should recognize all three.

Yes. I simply means and.

So the sentence has two linked parts:

• A la nit em fa mal la panxa
• i no vull sopar

= At night my stomach hurts and I don’t want to have dinner

One thing to remember: Catalan i is always written i, even before words that begin with an i sound. It does not change the way Spanish y sometimes does.

It can correspond to either dinner or supper in English, depending on the speaker’s variety of English and eating habits.

In Catalan, esmorzar, dinar, and sopar are the standard meal words:

• esmorzar = breakfast
• dinar = lunch / main midday meal
• sopar = evening meal, so dinner or supper

So in this sentence, no vull sopar means I don’t want to eat the evening meal.

Yes, very natural.

A la nit em fa mal la panxa i no vull sopar sounds like something a child or an adult might genuinely say in normal conversation.

It is especially natural because:

• A la nit is a common time phrase
• em fa mal la panxa is a very common way to talk about stomach pain
• no vull sopar is a normal everyday expression

So this is a good, useful sentence to learn as a chunk.