Escuchar música me anima cuando estoy triste.

Because escuchar is being used as an infinitive, and in Spanish an infinitive can act like a noun or noun phrase.

So Escuchar música means something like:

• listening to music
• to listen to music (in a general sense)

In this sentence, Escuchar música is the subject of anima.

So the structure is:

• Escuchar música = subject
• me anima = cheers me up

This is very natural in Spanish. English can do something similar with Listening to music cheers me up.

It is anima because the subject is Escuchar música, which is treated as a third-person singular idea.

So:

• Escuchar música = one activity / one whole idea
• therefore the verb is anima

It is not animo because I am not the subject.

It is not animan because the subject is not plural.

A helpful way to think of it is:

• Escuchar música = Listening to music
• Listening to music cheers me up

Since listening to music is singular in meaning, Spanish uses anima.

Me means me, and it tells you who receives the action of the verb.

So:

• anima = cheers up / encourages
• me anima = cheers me up

Literally, the structure is:

• Escuchar música = listening to music
• me anima = cheers me up

In this sentence, me is the object pronoun referring to the person being affected.

Not always. Animar can have a few related meanings, depending on context, such as:

• to cheer up
• to encourage
• to motivate
• to liven up

In Escuchar música me anima, the most natural meaning is cheers me up or lifts my spirits, because the sentence continues with cuando estoy triste.

So here, the emotional meaning is the important one.

Because escuchar música usually means to listen to music in a general sense.

In Spanish, when talking about an activity in general, you often do not use the article after verbs like this.

So:

• escuchar música = to listen to music generally
• escuchar la música = to listen to the music, usually some specific music

Compare:

• Me gusta escuchar música. = I like listening to music.
• Escucho la música que has puesto. = I’m listening to the music you put on.

In your sentence, the general idea is intended, so música appears without la.

Because estar is used for a temporary state or condition, while ser is used more for identity, essential characteristics, or permanent descriptions.

Here, triste means sad, and sadness is being treated as a temporary emotional state.

So:

• estoy triste = I am sad
• soy triste = I am a sad person / I am gloomy by nature

That second one would sound very different and much less natural in this context.

So cuando estoy triste means when I’m sad in the sense of when I’m feeling sad.

Triste is one of those adjectives that has the same form for masculine and feminine.

So you get:

• estoy triste = I am sad
• ella está triste = she is sad
• él está triste = he is sad

Only the number changes:

• triste = singular
• tristes = plural

Examples:

• Estoy triste.
• Estamos tristes.

So there is no masculine/feminine change here.

Not exactly.

• Escuchar música = the activity of listening to music
• La música = music itself

So:

• Escuchar música me anima = Listening to music cheers me up
• La música me anima = Music cheers me up

Both are possible, but they are slightly different in focus.

The original sentence emphasizes the action/activity of listening.

Yes. Spanish word order is quite flexible.

You could also say:

• Cuando estoy triste, escuchar música me anima.

This means the same thing, but it puts the time/condition first: When I’m sad, listening to music cheers me up.

The original order is also natural:

• Escuchar música me anima cuando estoy triste.

That version starts with the main idea: Listening to music cheers me up.

Only if it is already clear from context what it is.

In the full sentence, Escuchar música is the thing that cheers you up.

If you just say:

• Me anima cuando estoy triste

it means:

• It cheers me up when I’m sad

But the listener would need to know what it refers to.

So the full sentence is clearer when introducing the idea for the first time.

Because Spanish often leaves out subject pronouns when they are not needed.

So instead of saying:

• yo estoy triste

Spanish usually just says:

• estoy triste

The verb form estoy already tells us the subject is I.

Including yo is possible, but it is usually only used for emphasis, contrast, or clarity.

So:

• cuando estoy triste = the normal, natural wording
• cuando yo estoy triste = more emphatic or contrastive

Yes, it is completely natural in Spain Spanish.

Everything in the sentence is standard and widely used:

• escuchar música
• me anima
• cuando estoy triste

A speaker from Spain would understand and use this structure naturally.

Both are natural, but the nuance is a bit different.

• me anima = cheers me up / lifts me
• me pone de buen humor = puts me in a good mood

So:

• Escuchar música me anima cuando estoy triste focuses on the idea of becoming more emotionally encouraged or lifted.
• Escuchar música me pone de buen humor cuando estoy triste focuses more specifically on mood.

The original sentence is shorter and very natural.