Mi padre decía que solo quería mirar el mar, pero acabó por sentarse en la tumbona y quedarse dormido un rato.

Decía is the imperfect, while dijo is the preterite.

Here, decía que... suggests a repeated, ongoing, or background idea: my father used to say / was saying that... It sets the scene rather than presenting a single completed statement.

Using dijo que... would sound more like one specific occasion when he said it.

So in this sentence, decía helps create the feeling of background narration: he was saying he only wanted to look at the sea, but then something else happened.

For a similar reason, quería is the imperfect of querer, and it expresses an ongoing intention or desire: he wanted / he was saying he wanted.

If you used quiso, it would sound more like a completed event: he tried / he wanted to at that moment.

In this sentence, solo quería mirar el mar presents his intention as something in progress or as part of the background, not as a single completed action.

Here solo means only.

So solo quería mirar el mar = he only wanted to look at the sea.

In modern standard spelling, the adverb solo is normally written without an accent. In the past, some people wrote sólo to distinguish it from the adjective solo meaning alone, but today the accent is usually omitted unless there is real ambiguity.

So this spelling is completely normal:

• solo = only
• solo = alone

Context usually makes the meaning clear.

Both verbs relate to seeing, but they are not exactly the same.

• ver = to see
• mirar = to look at

Mirar el mar emphasizes the deliberate action of looking at the sea. It matches the idea that he intended to sit there and gaze at it.

If you said ver el mar, it would be more like simply seeing the sea, not necessarily intentionally looking at it.

Acabar por + infinitive means to end up doing something or to finally do something after some development.

So:

• acabó por sentarse... = he ended up sitting down...

It often suggests that the final result was not necessarily the original intention.

That fits the sentence well:

• he said he only wanted to look at the sea,
• but in the end he sat down and fell asleep.

Not always. You can often hear both:

• acabó por sentarse
• acabó sentándose

Both can mean he ended up sitting down.

The version with por + infinitive is very common and often sounds a bit more formal or literary. The version with the gerund, acabó sentándose, is also very natural.

So yes, por belongs to a normal fixed structure here.

Both verbs are normally used this way in these meanings.

• sentarse = to sit down
• quedarse = to remain / to end up / to become in a certain state

In Spanish, many verbs that English speakers do not think of as reflexive are reflexive in normal usage.

Examples:

• sentar = to seat something / to suit someone
• sentarse = to sit down
• quedar = to arrange / to remain / to be left
• quedarse dormido = to fall asleep

So the reflexive pronoun is not optional here; it is part of the verb as used in this sentence.

Quedarse dormido means to fall asleep.

Literally, it is something like to stay/remain asleep, but in actual usage it means the moment or result of drifting off.

So:

• se quedó dormido = he fell asleep
• quedarse dormido un rato = to fall asleep for a while

This is a very common Spanish expression.

In quedarse dormido, dormido is an adjective-like past participle describing the state the person ends up in.

The structure is:

• quedarse + adjective/participle

Examples:

• quedarse solo = to be left alone
• quedarse quieto = to stay still
• quedarse dormido = to fall asleep

So dormido describes the resulting state: he ended up asleep.

Tumbona is a sun lounger, deck chair, or reclining beach chair.

In Spain, this word is very common for the kind of chair you lie back on at the beach or by a pool.

It comes from the idea of tumbarse, meaning to lie down.

A learner of Latin American Spanish might meet other words in some regions, but tumbona is very natural in Spain.

Spanish often uses en where English might use several different prepositions.

• sentarse en la tumbona = to sit down on the sun lounger

Even though English says on, Spanish normally says en for sitting on chairs, sofas, benches, beds, etc.

Examples:

• sentarse en una silla
• sentarse en el sofá
• sentarse en la cama

So en la tumbona is exactly what you would expect in Spanish.

Un rato means a while or for a bit.

So:

• quedarse dormido un rato = to fall asleep for a while

It is a very common everyday expression. The exact length is vague, just like a while in English.

Because Spanish very often uses time expressions directly without a preposition.

So these are natural:

• dormir un rato
• esperar un momento
• trabajar toda la tarde

In English, you often need for, but Spanish often does not.

So quedarse dormido un rato is perfectly normal.

Because decir que... means to say that...

So:

• Mi padre decía que solo quería mirar el mar = My father was saying that he only wanted to look at the sea

The word que introduces the content of what was said, just like that in English.

In English, that can often be omitted:

• He said he wanted...

In Spanish, que is normally kept:

• Dijo que quería...

The first infinitive depends directly on acabó por:

• acabó por sentarse... = he ended up sitting down...

Then the second infinitive is joined with y:

• ...y quedarse dormido un rato = ...and falling asleep for a while

So the whole sequence means:

• he ended up sitting down on the sun lounger and falling asleep for a while

Spanish often avoids repeating the finite verb when one verb governs a chain of infinitives.

Spanish often uses the definite article with nouns where English may omit it.

Here el mar means the sea, and it sounds natural because it refers to the general visible sea in that setting.

After mirar, Spanish normally wants the object clearly marked:

• mirar el mar
• mirar la playa
• mirar el cielo

So mirar mar would sound incomplete or unnatural here.

Not usually in natural English. A more idiomatic translation is:

• but he ended up sitting down...
• but in the end he sat down...

Although acabar often means to finish, in the expression acabar por + infinitive the meaning is closer to end up or eventually do.

So literal translation would miss the normal idiomatic meaning.