Quiero ir a la biblioteca.

In Spanish, the subject pronoun (like yo = I) is often dropped because the verb ending already shows who the subject is.

• Quiero means I want (first person singular).
• So yo quiero and quiero usually mean the same thing.

You only add yo for emphasis or contrast, e.g.:

• Yo quiero ir, pero ella no quiere. – I want to go, but she doesn’t.

Some Spanish verbs are followed directly by another verb in the infinitive. Querer is one of them.

Pattern:

• Conjugated verb + infinitive
• Quiero ir = I want to go
• Queremos comer = We want to eat
• ¿Quieres salir? = Do you want to go out?

You don’t add anything like “to” in between; the infinitive itself (ir, comer, salir) covers the idea of “to + verb”.

English says “want to go”. Spanish does it differently:

• Quiero ir literally = I want go (but grammatically correct in Spanish).
• The “to” is built into the infinitive ir.

So:

• to go → ir
• to eat → comer
• to read → leer

You don’t translate “to” separately before an infinitive.

The preposition a is needed because the verb ir (to go) expresses movement to a place.

• ir a = to go to
• ir a la biblioteca = to go to the library

Other examples:

• Voy al parque. – I’m going to the park.
• Vamos al cine. – We’re going to the cinema.

So with verbs of movement (ir, venir, llegar…), you usually need a before the destination.

Al is a contraction of a + el (to + the, masculine singular):

• a + el = al (masculine)
  • al parque, al museo

But biblioteca is feminine:

• la biblioteca (the library)

So:

• a + la stays a la (no contraction)
  • a la biblioteca
  • a la playa
  • a la estación

This is a classic false friend:

• biblioteca = library (a place where you borrow or use books, usually free)
• librería = bookshop / bookstore (a place where you buy books)

So:

• Quiero ir a la biblioteca. – I want to go to the library.
• Quiero ir a la librería. – I want to go to the bookshop.

It’s not more correct; it’s just more explicit.

• Quiero ir a la biblioteca. – neutral, very normal.
• Yo quiero ir a la biblioteca. – adds emphasis to I.

You might use yo:

• To contrast: Yo quiero ir, pero tú no quieres.
• To emphasize: Yo quiero ir, de verdad. – I really do want to go.

Quiero ir a la biblioteca is neutral and fine in many contexts, especially when just stating a fact:

• Talking to friends or family
• Explaining what you want to do

But if you’re asking for something (e.g., to a stranger, a waiter, a librarian), Spanish often prefers softer forms:

• Me gustaría ir a la biblioteca. – I’d like to go to the library.
• Querría ir a la biblioteca. – I would like to go to the library.
• ¿Podría ir a la biblioteca? – Could I go to the library?

Quiero… can sound a bit blunt in requests, especially in Spain, so softer options are common for politeness.

Querer is a stem‑changing verb (e → ie) in the present tense.

For querer (to want):

• yo quiero – I want
• tú quieres – you want
• él / ella / usted quiere – he/she/you (formal) want(s)
• nosotros queremos – we want
• vosotros queréis (Spain) – you all want
• ellos / ellas / ustedes quieren – they / you all want

Notice how quer- changes to quier- in most forms, but not in nosotros and vosotros. This is a regular pattern for many stem‑changing verbs.

You can, but it sounds different:

• Quiero ir a la biblioteca. – Most common, everyday way to say I want to go to the library.
• Deseo ir a la biblioteca. – More formal or literary; in everyday speech it can sound a bit dramatic or too strong.

In normal conversation in Spain, querer is far more frequent than desear when talking about what you want to do.

No, that word order is not natural in Spanish.

The normal pattern is:

• Quiero + infinitive + rest of the sentence
• Quiero ir a la biblioteca.

Spanish word order is a bit flexible, but splitting quiero and ir like Quiero a la biblioteca ir sounds wrong. You might sometimes move the place phrase:

• A la biblioteca quiero ir. – Possible, but sounds marked/emphatic, like “To the library is where I want to go.”
  For a learner, stick with Quiero ir a la biblioteca.

In Spanish, you normally need the definite article with most singular countable nouns:

• la biblioteca – the library
• el museo – the museum
• la estación – the station

So:

• Quiero ir a la biblioteca. – correct
• Quiero ir a biblioteca. – sounds wrong in standard Spanish.

There are some exceptions (e.g. a casa, a clase, sometimes a misa), but biblioteca is not one of them. You generally say a la biblioteca.

Spanish a has several uses. Here it marks direction / destination:

• ir a un lugar – to go to a place
  
  • ir a la biblioteca
  • ir al cine
  • ir a Madrid

The personal a is different: it’s used before direct objects that are specific people (or certain animals):

• Veo a María. – I see María.
• Llamo a mi hermano. – I call my brother.

In Quiero ir a la biblioteca, the a is not a personal a; it’s just the “to” of movement toward a place.