Mi hermana quiere rallar zanahoria para la ensalada de hoy.

Because after querer when you mean to want to do something, Spanish normally uses:

querer + infinitive

So:

• Mi hermana quiere rallar zanahoria = My sister wants to grate carrot

The second verb stays in the infinitive:

• quiero comer = I want to eat
• queremos salir = we want to go out

You would not say quiere ralla here, because after quiere, the next verb should be the infinitive: rallar.

Rallar means to grate or to shred food into small pieces, usually with a grater.

Examples:

• rallar queso = to grate cheese
• rallar zanahoria = to grate carrot
• rallar limón can also mean to grate lemon peel/zest, depending on context

Be careful not to confuse it with similar-looking words like rayar, which usually means to scratch, to draw lines, or informally to annoy / drive someone crazy.

Both can be possible, but they do not feel exactly the same.

In rallar zanahoria, the noun is being used in a more general, ingredient-like way, similar to:

• comer pan
• beber agua
• comprar queso

It focuses on the substance or ingredient rather than a specific individual carrot.

If you say rallar la zanahoria, it sounds more like a specific carrot or a specific quantity already understood in the situation:

• Ralla la zanahoria que compré ayer = Grate the carrot I bought yesterday

So in a recipe or food-preparation context, omitting the article is very natural.

Yes, but the meaning shifts a little.

• rallar zanahoria = grate carrot / grated carrot as an ingredient
• rallar las zanahorias = grate the carrots (specific carrots)
• rallar zanahorias = grate carrots (plural, more countable/general than the mass-like singular)

Spanish often uses the singular with food ingredients in a broad, material sense:

• lleva cebolla
• necesito tomate
• vamos a cortar patata

So zanahoria here sounds very natural as an ingredient.

Para here expresses purpose or intended use:

• rallar zanahoria para la ensalada = to grate carrot for the salad

It answers the question What for?

Compare:

• Estudio para el examen = I study for the exam
• Compré pan para la cena = I bought bread for dinner

So para la ensalada de hoy means the grated carrot is intended for today's salad.

La ensalada de hoy literally means the salad of today, but in natural English that is usually today's salad or the salad for today.

The structure noun + de + time expression is very common in Spanish:

• la clase de hoy = today's class
• la reunión de mañana = tomorrow's meeting
• el partido de anoche = last night's match

So de hoy identifies which salad: the one for today.

Yes, but it would mean something different.

• Mi hermana quiere rallar zanahoria para la ensalada de hoy = My sister wants to grate carrot for today’s salad
• Mi hermana quiere rallar zanahoria para hoy = My sister wants to grate carrot for today

The second version is less specific. It tells you the action is for today, but not exactly for what. The original sentence is clearer because it names the purpose: the salad.

Because mi hermana is the subject of the sentence: the person doing the wanting.

• Mi hermana quiere... = My sister wants...

You use a before a person mainly when that person is a direct object, not the subject:

• Veo a mi hermana = I see my sister

But here your sister is not the object; she is the one who wants to do the action.

In standard Spanish, rr is a strong rolled/trilled r.

So rallar is pronounced with:

• a trill in rr
• and in Spain, the ll is usually pronounced like the y in yes (though exact pronunciation varies)

A rough guide:

• ra-
  • rolled rr
    • yar

Important contrast:

• caro = expensive (single r, softer sound)
• carro = cart/car (double rr, trilled sound)

For many learners, rr takes practice. It is normal if it feels difficult at first.

In most of Spain, the z in zanahoria is pronounced like the th in think.

So it sounds roughly like:

• tha-na-O-ria

A few pronunciation notes:

• z in most of Spain = th sound
• h is silent
• the stress falls on -ho-: zanaHOria

In much of Latin America, the z would sound more like an s.

Yes, it sounds natural.

A speaker from Spain would understand it immediately, and the wording is normal:

• Mi hermana quiere... is a standard way to say My sister wants to...
• rallar zanahoria works well in a cooking context
• para la ensalada de hoy is a natural way to specify the purpose

A slightly more specific version could be:

• Mi hermana quiere rallar la zanahoria para la ensalada de hoy
• Mi hermana quiere rallar zanahorias para la ensalada de hoy

But the original sentence is perfectly fine.

No, not in this sentence.

Querer can sometimes mean to love, especially with people:

• Te quiero = I love you / I care about you

But when querer is followed by an infinitive, it means to want:

• quiere rallar = wants to grate

So in this sentence, there is no ambiguity.

Not in natural English.

A word-for-word translation may help you see the structure, but good English would be:

• My sister wants to grate carrot for today’s salad.
• or My sister wants to grate some carrot for today’s salad.

Key differences:

• English needs to after wants
• the salad of today is understandable, but natural English prefers today’s salad

So a literal breakdown is useful for learning, but not for final translation.