Learn Hardcore Spanish (Spain): Hoy solo quiero descansar en casa.

quiero (ending in -o) can only mean I want.
So Hoy solo quiero descansar en casa already means Today I only want to rest at home, with I understood.

You add yo mainly for emphasis or contrast:

Yo quiero descansar, pero tú quieres salir.
(I want to rest, but you want to go out.)

In neutral, everyday speech, leaving yo out here is more natural.

What does solo mean here? Is it only or alone?

In this sentence, solo is an adverb meaning only:

Hoy solo quiero descansar en casa.
Today I only want to rest at home.
→ The only thing I want to do is rest.

If you wanted to say I want to rest alone at home, the position changes:

Hoy quiero descansar solo en casa.

Now solo describes how you rest (alone), not what you want (only to rest).
So:

solo quiero descansar → I only want to rest.
quiero descansar solo → I want to rest alone.

Word order matters a lot for the meaning here.

Why is solo written without an accent? I’ve seen sólo before.

The word solo used to be written with an accent (sólo) when it meant only, to distinguish it from solo meaning alone.

However, the current recommendation from the Real Academia Española (RAE) is:

Write solo without an accent in almost all cases, even when it means only.
The accent sólo is now considered unnecessary and is rarely recommended.

So Hoy solo quiero descansar en casa is the modern, standard spelling in Spain.

Can I use solamente instead of solo? Do they mean the same thing?

Yes, in this sentence solo and solamente are interchangeable as adverbs meaning only:

Hoy solo quiero descansar en casa.
Hoy solamente quiero descansar en casa.

Both are correct. Solo is shorter and more common in speech. Solamente can sound a bit more formal or emphatic, but the difference is small.

Why is descansar in the infinitive? Why not something like descanso?

In Spanish, many verbs of desire, intention, or preference are followed by another verb in the infinitive. Querer is one of them:

querer + infinitive = to want to + verb

So:

quiero descansar = I want to rest
(literally: I want to rest)

Using descanso (I rest) would change the meaning:

Hoy solo descanso en casa.
= Today I only rest at home.
(a statement of fact about today, not what you want to do)

In the original sentence, you are expressing a desire/intention, so you need quiero descansar.

Why is it en casa and not a casa or en la casa?

These forms mean different things:

en casa = at home (general, your home)
- Hoy solo quiero descansar en casa.
  Today I only want to rest at home.
a casa = (to) home, indicates movement towards home
- Voy a casa.
  I’m going home.
en la casa = in the house, but usually a specific house, not necessarily your home
- Hay mucho ruido en la casa de al lado.
  There is a lot of noise in the house next door.

In the original sentence, you are focusing on staying at home, so en casa is the natural choice.

Do I need to say en mi casa instead of en casa?

You can say en mi casa, but you don’t need to.

en casa in Spanish is normally understood as at (my) home, unless the context suggests otherwise.
en mi casa adds explicit emphasis that it is my home, which can be useful if there might be confusion.

So:

Hoy solo quiero descansar en casa.
→ Natural, neutral: at home (my home).
Hoy solo quiero descansar en mi casa.
→ Emphasising my house, maybe in contrast with someone else’s place.

In most everyday contexts, en casa is enough.

What tense is quiero, and why is it used to talk about something I’ll do today?

Quiero is the present indicative of querer:

yo quiero = I want.

Spanish often uses the present tense to express near-future plans or intentions, especially with time expressions like hoy, mañana, esta noche:

Mañana trabajo. → I’m working tomorrow.
Esta noche cenamos fuera. → We’re having dinner out tonight.

So Hoy solo quiero descansar en casa means both:

literally: Today I only want to rest at home
functionally: you are talking about what you plan/intend to do today.

Using the present here is completely natural in Spain.

Can I move hoy or solo to other positions? Does the meaning change?

Yes, word order is flexible, and it affects emphasis:

Hoy solo quiero descansar en casa.
Neutral, typical order. Focus: what you want to do today is only rest at home.
Solo hoy quiero descansar en casa.
Now solo modifies hoy → only today I want to rest at home (not on other days).
Hoy quiero solo descansar en casa.
Stronger emphasis that the only thing you want is to rest at home (nothing else: no going out, no working, etc.).

Grammatically all are fine, but be careful: moving solo can change whether it means only today or only rest.

Is there any difference between descansar and relajarme in this kind of sentence?

Yes, they are related but not identical:

descansar = to rest, to stop working or exerting yourself, to recover energy
relajarse / relajarme = to relax, to unwind, to reduce stress or tension

In your sentence:

Hoy solo quiero descansar en casa.
→ I’m tired; I don’t want to do activities, I just want to rest.

You could also say:

Hoy solo quiero relajarme en casa.
→ I want to chill, unwind, maybe watch TV, lie on the sofa, etc.

Both are natural in Spain, but descansar focuses more on physical or mental rest; relajarme focuses more on relaxing as a state/feeling.

How do you pronounce each word in Hoy solo quiero descansar en casa in Spain?

Approximate pronunciation in standard peninsular Spanish:

Hoy → like oy in boy, but without the initial b sound: [oi]
solo → SOH-loh (SO like in so, lo like in low but shorter)
quiero → KYEH-roh
- qu = k sound
- ie = like ye in yes but as one syllable
descansar → des-kan-SAR
- d soft, c before a = k
- stress on -sar
en → like en in send but without the final d: en
casa → KAH-sa
- c before a = k, s like English s
- stress on CA

In most of Spain, s in solo and c in casa are pronounced the same [s] sound.