Learn Hardcore Polish: Dwa lata temu byłem w Hiszpanii.

dwa – for masculine inanimate and neuter nouns:
- dwa lata, dwa domy (two houses)
dwie – for feminine nouns:
- dwie godziny (two hours)
dwóch / dwu / dwoma – other case forms, often with masculine personal or in oblique cases (more advanced).

Here, lata (from rok) is treated as masculine inanimate, so you use dwa lata, not dwie lata or dwóch lata.

What exactly does temu do, and where does it go in the sentence?

Temu here means “ago”.

It comes after the time expression:
- rok temu – a year ago
- dwa lata temu – two years ago
- pięć minut temu – five minutes ago
It does not change its form in this use (you always say temu, never temem, temuś, etc., in this meaning).
The whole phrase dwa lata temu functions like an adverb (“when?”).

You cannot put temu at the very beginning like in English “ago two years I was in Spain”; in Polish it must follow the time phrase: dwa lata temu.

Can I change the word order of Dwa lata temu byłem w Hiszpanii?

Yes. Polish word order is flexible. Common variants:

Dwa lata temu byłem w Hiszpanii. – neutral; light emphasis on when.
Byłem w Hiszpanii dwa lata temu. – neutral; light emphasis on where, then when.
W Hiszpanii byłem dwa lata temu. – emphasizes Spain (e.g. “It was Spain that I was in two years ago”).

All are grammatical. In normal speech you’ll most often hear:

Dwa lata temu byłem w Hiszpanii.
Byłem w Hiszpanii dwa lata temu.

Why is it byłem and not jestem or some other tense?

Byłem is the past tense of być (“to be”), 1st person singular, masculine:

jestem – I am (present)
byłem – I was (past, said by a man/boy)
byłam – I was (past, said by a woman/girl)

Because the sentence talks about something two years in the past, you must use the past tense: byłem (or byłam for a female speaker), not jestem.

Why does byłem show my gender? In English, I was is the same for everyone.

In Polish, the past tense form of most verbs shows:

person (I, you, he…)
number (singular/plural)
gender (in the singular)

For być (to be), the main singular past forms are:

ja byłem – I was (male speaker)
ja byłam – I was (female speaker)
ty byłeś – you were (male)
ty byłaś – you were (female)
on był, ona była, ono było – he was, she was, it was

So:

A man would say: Dwa lata temu byłem w Hiszpanii.
A woman would say: Dwa lata temu byłam w Hiszpanii.

Why is ja (“I”) missing? Do I always have to say ja?

In Polish, subject pronouns (ja, ty, on, etc.) are usually dropped because the verb form already shows person (and in the past, also gender):

Byłem w Hiszpanii. – I was in Spain. (spoken by a man)
Byłam w Hiszpanii. – I was in Spain. (spoken by a woman)

You only add ja for emphasis or contrast:

Ja byłem w Hiszpanii, a on był we Włoszech.
I was in Spain, and he was in Italy.

So Ja dwa lata temu byłem w Hiszpanii is possible but sounds emphatic, not neutral.

Why is it w Hiszpanii, not w Hiszpania?

The preposition w (“in”) usually requires the locative case when it means location (“in, inside”):

Hiszpania – Spain (nominative, dictionary form)
w Hiszpanii – in Spain (locative)

So the pattern is:

w + locative → w Polsce, w Hiszpanii, w domu, w kinie

That’s why the country name changes to Hiszpanii after w in this context.

How does Hiszpania decline? What are the main forms I should know?

Hiszpania (“Spain”) is a regular feminine noun ending in -a. Singular forms you’ll most often meet:

Nominative (who? what?) – Hiszpania
- Hiszpania jest w Europie.
Genitive (of whom? of what?) – Hiszpanii
- stolica Hiszpanii – the capital of Spain
Dative (to whom? to what?) – Hiszpanii
- przyglądam się Hiszpanii (less common)
Accusative (whom? what?) – Hiszpanię
- jadę do Hiszpanii – I’m going to Spain
Instrumental (with whom? with what?) – Hiszpanią
- interesuję się Hiszpanią – I’m interested in Spain
Locative (about/in whom? what?) – Hiszpanii
- byłem w Hiszpanii – I was in Spain

So in w Hiszpanii, you’re seeing the locative form.

What’s the difference between w Hiszpanii and do Hiszpanii?

w Hiszpanii – “in Spain” (location, where you are / were)
- byłem w Hiszpanii – I was in Spain
do Hiszpanii – “to Spain” (direction, movement towards)
- jadę do Hiszpanii – I’m going to Spain
- pojechałem do Hiszpanii – I went to Spain

Compare:

Dwa lata temu byłem w Hiszpanii. – Two years ago I was in Spain.
Dwa lata temu pojechałem do Hiszpanii. – Two years ago I went to Spain.

Could this sentence also mean “I’ve been to Spain” (present perfect), not just “I was in Spain”?

Polish does not have a separate present perfect tense like English. The simple past often covers both:

Dwa lata temu byłem w Hiszpanii.

In context, this can correspond to:

“I was in Spain two years ago.”
as an answer to “Have you ever been to Spain?”:
– Tak, dwa lata temu byłem w Hiszpanii.
“Yes, I was in Spain two years ago / I’ve been to Spain – two years ago.”

If you want to emphasize “at some time in my life” (experience), you can also add kiedyś:

Kiedyś byłem w Hiszpanii. – I’ve been to Spain (at some point).

Is there any difference between dwa lata temu and przed dwoma laty?

Both mean “two years ago”, but they differ in style and frequency:

dwa lata temu – the most common, neutral, everyday phrase.
przed dwoma laty – more formal / literary, sounds a bit old-fashioned or elevated in modern speech.

In normal conversation you will almost always hear:

Dwa lata temu byłem w Hiszpanii.

Przed dwoma laty byłem w Hiszpanii is correct but sounds more like written style or very formal speech.

Can I say bywałem w Hiszpanii instead of byłem w Hiszpanii?

You can, but the meaning changes:

byłem w Hiszpanii – I was in Spain (once, or speaking about a specific visit).
bywałem w Hiszpanii – I used to be in Spain / I would be in Spain (repeated or habitual visits in the past).

Examples:

Dwa lata temu byłem w Hiszpanii.
I went / was there two years ago (one specific time).
Kiedy pracowałem jako pilot wycieczek, często bywałem w Hiszpanii.
When I worked as a tour guide, I often used to be in Spain.

In your sentence, because you mention a specific time (“two years ago”), byłem is the natural choice.