Learn Hardcore Spanish (Spain): El sábado pasado estudié español en la biblioteca. - Last Saturday I studied Spanish in the library.

So the article el is required and sounds natural to Spanish speakers. Leaving it out (sábado pasado) would sound incomplete or odd in standard Spanish.

Why is it sábado pasado and not pasado sábado, like last Saturday?

In Spanish, most adjectives usually come after the noun, not before it as in English:

coche rojo – red car
libro interesante – interesting book

Time adjectives like pasado often follow the same pattern:

el año pasado – last year
el mes pasado – last month
el sábado pasado – last Saturday

You can say el pasado sábado, but:

el sábado pasado is the most common, neutral way to say last Saturday.
el pasado sábado is correct but less frequent and can sound more formal or slightly more emphatic in some contexts.

So el sábado pasado is the default choice.

Why is estudié used here and not estudiaba?

Both estudié and estudiaba are past tenses, but they express different ideas:

estudié = preterite (pretérito indefinido)
- Used for completed actions in the past, seen as finished events.
- e.g. Ayer estudié tres horas. – Yesterday I studied for three hours (and it’s done).
estudiaba = imperfect (pretérito imperfecto)
- Used for ongoing, repeated, or background actions in the past.
- e.g. Cuando era niño, estudiaba español. – When I was a child, I used to study Spanish.

In El sábado pasado estudié español en la biblioteca, the speaker is talking about a specific, completed event last Saturday. That fits the preterite, so estudié is the correct choice.

How is estudié formed, and what does the accent do?

Estudié is the yo (I) form of the preterite of estudiar (to study).

For regular -ar verbs in the preterite, the endings are:

yo: -é → estudié – I studied
tú: -aste → estudiaste – you studied
él/ella/usted: -ó → estudió – he/she/you (formal) studied
nosotros: -amos → estudiamos – we studied
vosotros: -asteis → estudiasteis
ellos/ellas/ustedes: -aron → estudiaron

The accent on -é shows:

Where the stress falls: es-tu-dié (last syllable).
That it’s the preterite yo form, not a different tense or form.

Without the accent (estudie), it would normally be read as present subjunctive, not past.

Where is yo? Why doesn’t the sentence say Yo estudié?

Spanish is a pro-drop language: subject pronouns (yo, tú, él, ella, etc.) are often omitted because the verb ending already shows the subject.

estudié can only mean I studied (yo).
Adding yo is only needed for emphasis or contrast:
- Yo estudié, pero él no estudió. – I studied, but he didn’t.

So El sábado pasado estudié español en la biblioteca is completely natural and clear without yo.

Why is it en la biblioteca and not a la biblioteca?

en = in / at (location where something happens)
a = to (movement toward a place)

In this sentence, the action happens in the library, it doesn’t describe going there:

Estudié español en la biblioteca. – I studied Spanish in/at the library.

If you wanted to express movement, you’d use a:

Fui a la biblioteca para estudiar. – I went to the library to study.

So for the place where the studying happened, en la biblioteca is the correct preposition.

Why is it la biblioteca and not el biblioteca?

In Spanish, every noun has a grammatical gender:

Words ending in -a are often feminine (not always, but often).
biblioteca is a feminine noun.

Feminine singular nouns use the article la:

la biblioteca – the library
la casa – the house
la mesa – the table

So la biblioteca is correct because biblioteca is feminine.

Why is there no article before español? Why not el español?

In this sentence, español is the subject you’re studying, like a school subject:

Estudié español. – I studied Spanish (as a subject).

When talking about languages as school subjects, it’s very common (and natural) not to use the article:

Estudio inglés y alemán. – I study English and German.

El español is also possible, but it slightly shifts focus to the Spanish language itself as an entity:

Estudié el español de Cervantes. – I studied the Spanish of Cervantes.

In your sentence, Estudié español is the most typical way to say I studied Spanish as a subject.

Why aren’t sábado and español capitalized in Spanish?

In Spanish:

Days of the week are written with lowercase:
- lunes, martes, miércoles, jueves, viernes, sábado, domingo
Languages and nationalities are also lowercase:
- español, inglés, francés
- español, inglés, francés (as adjectives: Spanish, English, French)

So:

El sábado pasado estudié español…

is correctly written with sábado and español in lowercase, even though in English we capitalize Saturday and Spanish.

Does el sábado pasado always mean the Saturday just before today?

Normally, el sábado pasado means the most recent Saturday before today:

If today is Wednesday, el sábado pasado = the Saturday 4 days ago.
If today is Monday, el sábado pasado = the Saturday 2 days ago.

If someone wants to talk about some earlier Saturday, they usually add more information:

El sábado de la semana pasada… – The Saturday of last week…
El sábado anterior a Navidad… – The Saturday before Christmas…

So by default, el sábado pasado is understood as the most recent Saturday.

Can the word order change? For example, can I say El sábado pasado, en la biblioteca, estudié español?

Yes. Spanish allows some flexibility in word order, especially with time and place expressions.

All of these are grammatically correct, just with slightly different emphasis:

El sábado pasado estudié español en la biblioteca.
El sábado pasado, en la biblioteca, estudié español.
En la biblioteca, el sábado pasado, estudié español.

In everyday speech, the most neutral and common is usually:

El sábado pasado estudié español en la biblioteca.

Moving en la biblioteca to the beginning (or between commas) can add emphasis to the location.

Can I say Pasado sábado estudié español?

No, that sounds wrong in Spanish.

You have two natural patterns:

el sábado pasado – last Saturday (most common)
el pasado sábado – last Saturday (less common, slightly more formal/emphatic)

But pasado sábado without an article and in that order is not used in standard Spanish. You need:

El sábado pasado estudié español en la biblioteca.

How would estudié change for other people (you, he/she, we, etc.)?

Here is the full preterite of estudiar:

yo estudié – I studied
tú estudiaste – you (informal singular) studied
él / ella / usted estudió – he / she / you (formal) studied
nosotros / nosotras estudiamos – we studied
vosotros / vosotras estudiasteis – you (plural, informal, Spain) studied
ellos / ellas / ustedes estudiaron – they / you (plural, formal) studied

Examples with the same sentence:

El sábado pasado estudiaste español en la biblioteca. – You studied…
El sábado pasado estudió español en la biblioteca. – He/She/You (formal) studied…
El sábado pasado estudiamos español en la biblioteca. – We studied…

Could I say Fui a estudiar español a la biblioteca instead? What’s the difference?

Yes, that’s also correct, but it focuses on something slightly different:

Estudié español en la biblioteca.
- States the fact that you studied Spanish in the library.
- Focus = the action of studying and where it happened.
Fui a estudiar español a la biblioteca.
- Emphasizes that you went to the library in order to study Spanish.
- Focus = the movement/purpose (going to study).

Both can be used for the same real-life event, but the first centers on what you did, and the second on going there to do it.

Why does sábado have an accent?

Sábado has three syllables: sá-ba-do.

Spanish stress rules say:

Words ending in a vowel, -n, or -s are normally stressed on the second-to-last syllable.

If sábado followed the normal rule, it would be stressed on ba: sa-BA-do. But it’s actually pronounced SÁ-ba-do, so the accent mark is needed on sá to show the correct stress.

Without the accent (sabado), Spanish speakers would be forced by the rules to say sa-BA-do, which is wrong. The written accent corrects that.