Si estàs refredada, has de beure aigua i dormir més.

Catalan uses estar for many temporary states and conditions, including illnesses. So estàs refredada means you have a cold / you are sick with a cold.

• estar = to be, in a temporary state
• ser = to be, in a more essential or permanent sense

So here:

• estàs refredada = you have a cold / you’re cold-stricken

Using ets refredada would sound wrong in standard Catalan.

Because refredada is the feminine singular form. The sentence is addressing a woman or girl.

• refredat = masculine singular
• refredada = feminine singular

So:

• to a man: Si estàs refredat...
• to a woman: Si estàs refredada...

This is very common in Catalan: adjectives often agree in gender and number with the person they describe.

Here, refredada means having a cold.

It comes from refredat / refredada, which can refer to a cold or being affected by a cold. In this sentence, it functions like an adjective after estar.

So the structure is basically:

• estar refredada = to have a cold

English often uses have for illnesses, while Catalan may use estar + adjective.

Has de means you have to or you must.

It comes from:

• has = you have (from haver)
• de = to

Together, haver de + infinitive expresses obligation:

• has de beure = you have to drink
• has de dormir = you have to sleep

This is a very common Catalan structure. Even though it looks like have of, it really means have to.

Because after has de, Catalan uses the infinitive of the main verb.

So:

• has de beure = you have to drink
• has de dormir = you have to sleep

This is similar to English:

• have to drink
• have to sleep

The conjugated verb is has, and the following verbs stay in their base form.

Catalan often drops subject pronouns when they are already clear from the verb form.

So:

• estàs already tells you it means you are
• has already tells you it means you have

Because of that, tu is not necessary:

• Si estàs refredada... = If you have a cold...

You could say Si tu estàs refredada..., but that usually adds emphasis or contrast.

Because si without an accent means if.

Catalan distinguishes:

• si = if
• sí = yes

So in this sentence:

• Si estàs refredada... = If you have a cold...

The accent changes the meaning completely.

Més means more.

In dormir més, it means to sleep more.

So:

• dormir = to sleep
• dormir més = to sleep more

The accent on més is important. It helps distinguish it from mes, which can mean month in Catalan.

Because in Catalan, adverbs like més usually come after the infinitive in this kind of structure.

So the natural order is:

• dormir més = sleep more
• beure més aigua = drink more water

Més dormir would not sound natural here.

Yes, in many contexts you can. Constipat / constipada is also commonly used for having a cold.

Depending on region and preference, you may hear:

• estar refredat/refredada
• estar constipat/constipada

Both are common, though usage can vary across Catalan-speaking areas. If you are learning general Catalan, it is good to recognize both.

Because Catalan often uses nouns without an article in general statements, especially after verbs like beure when talking about the substance in a general sense.

So:

• beure aigua = to drink water

This is similar to English, where we usually say drink water, not drink the water, unless we mean specific water.

A rough pronunciation guide for an English speaker is:

• Si ≈ see
• estàs ≈ es-TAS
• refredada ≈ reh-freh-DA-də or reh-freh-DA-da depending on accent
• has de ≈ az də / as de
• beure ≈ BEW-rə
• aigua ≈ EYE-gwə
• i ≈ ee
• dormir ≈ dor-MEER
• més ≈ mess

A few useful notes:

• The accented syllables are -tàs, -da-, beu-, -mir, més
• i means and and is pronounced like ee
• Final unstressed vowels are often weaker than in English

Yes. Although has de literally expresses obligation, in a sentence like this it often sounds like practical advice:

• you have to drink water and sleep more
• you should drink water and sleep more

So grammatically it is obligation, but in everyday use it can function as a strong recommendation, especially in health-related contexts.