Fa dos dies que vull comprar xampú i un raspall per al cabell.

This is a very common Catalan way to express duration.

The pattern is:

fa + time expression + que + present-tense clause

So:

Fa dos dies que vull comprar...

means:

I’ve been wanting to buy... for two days

Literally, fa is the verb fer in the 3rd person singular and in this structure it works a bit like it has been.

You will see this pattern a lot in Catalan:

• Fa tres anys que viu aquí. = He/She has lived here for three years.
• Fa una setmana que no plou. = It hasn’t rained for a week.

Because Catalan often uses the present tense for an action or state that started in the past and is still continuing now.

So in English you often say:

• I have wanted
• I’ve been wanting

But in Catalan, with fa... que, the normal choice is usually the present:

• Fa dos dies que vull...

This tells us the wanting began two days ago and is still true now.

If you used a past form like he volgut here, it would usually sound more like a completed past event, not an ongoing state.

Here que links the duration expression to the rest of the sentence.

In this structure, que is a normal part of the pattern:

fa + time + que + clause

So you should learn fa dos dies que as a chunk meaning something like:

for two days now / it has been two days that...

It is not translating a separate English word very neatly; it is just part of how Catalan builds this expression.

Because voler is followed directly by an infinitive.

So the pattern is:

voler + infinitive

Examples:

• Vull menjar. = I want to eat.
• Volen sortir. = They want to go out.
• Vull comprar xampú. = I want to buy shampoo.

Unlike some other verbs in Romance languages, you do not put a preposition here.

Because xampú is being used as an uncountable / mass noun, while raspall is a countable object.

So:

• xampú = shampoo in general
• un raspall = one brush

This is similar to English:

• I want to buy shampoo and a brush

not necessarily:

• I want to buy a shampoo and a brush

If you were thinking of a specific bottle or type, un xampú could also be possible, but in this sentence xampú is just the substance/product in general.

It is generally masculine:

• el xampú
• un xampú

In this sentence there is no article before it, but that does not mean it has no gender. It just means the noun is being used in a more general, uncountable way.

Per al means for the.

It comes from:

per a + el = per al

So:

• per al cabell = for the hair

Here it tells you the purpose of the brush: it is a brush intended for hair.

So un raspall per al cabell is basically a hair brush / a brush for the hair.

In Catalan, el cabell in the singular can mean hair as a collective substance, much like English hair.

So:

• el cabell = hair in general
• els cabells = hairs / the hairs, or sometimes hair in a more countable or individual sense

That means per al cabell is perfectly normal for for the hair.

This is similar to English:

• Hair is usually uncountable
• Hairs is used when you mean individual strands

Yes, it is natural and understandable.

Catalan can express this idea in more than one way, for example:

• un raspall per al cabell
• un raspall de cabell

The version in your sentence emphasizes the purpose of the object: a brush for the hair.

A learner should mainly recognize that raspall means brush, and the rest specifies what kind of brush it is.

A rough guide:

• xampú ≈ sham-POO
• raspall ≈ ras-PY or ras-PALY, depending on dialect
• cabell ≈ ka-BEY or ka-BELL, depending on dialect

A few useful points:

• In xampú, the x is pronounced like English sh.
• The accent mark in xampú shows the stress falls on the last syllable: -pú.
• In raspall and cabell, the ll sound varies by dialect. In some accents it sounds somewhat like y, and in others it is a more distinct palatal ll sound.

The most important thing for a beginner is:

• stress xamPÚ
• stress rasPALL
• stress caBELL