Learn Hardcore Spanish (Latin America): Escribo cada noche tres cosas por las que siento gratitud. - Every night I write three things for which I feel gratitude.

Escribo can only mean “I write” in the present tense.
Because the -o ending already tells us the subject is yo, native speakers normally don’t say yo escribo unless they want to emphasize I (as opposed to someone else).

So:

Escribo cada noche… = normal, neutral
Yo escribo cada noche… = “I write every night…” (maybe in contrast to “you don’t”)

What’s the difference between cada noche and todas las noches?

Both usually translate as “every night”, but there’s a small nuance:

cada noche – a bit more individualizing: it highlights each night as a separate occasion.
todas las noches – more collective: emphasizes all nights as a group, regularly.

In practice, both are very common in Latin America and are almost always interchangeable in this kind of sentence:

Escribo cada noche tres cosas…
Escribo todas las noches tres cosas…

Both sound natural.

Why is there no article (la) in cada noche? Why not cada la noche?

With cada (“each / every”), you don’t use a definite article:

✅ cada noche – each/every night
❌ cada la noche – incorrect
✅ cada día, cada semana, cada año

But with todas, you usually do use an article:

✅ todas las noches – every night / all nights
✅ todas las semanas, todas las mañanas

Could I move cada noche? For example, say Cada noche escribo tres cosas… or Escribo tres cosas cada noche…?

Yes, all of these are grammatically correct and natural; the differences are subtle in emphasis:

Escribo cada noche tres cosas…
Neutral; slight focus on the activity (escribo) and its frequency (cada noche).
Cada noche escribo tres cosas…
Slightly more emphasis on “Every night, I…” — you foreground the time.
Escribo tres cosas cada noche…
More emphasis on “three things” as the unit you write each night.

In everyday speech and writing, all three word orders are fine.

What does por las que mean exactly, and why is it used here?

por las que literally means “for which” and introduces a relative clause:

tres cosas por las que siento gratitud
= “three things for which I feel gratitude”

Breaking it down:

por = “for” (cause/reason)
las = agrees with cosas (feminine plural)
que = relative pronoun “which / that”

So the structure is:
cosas (por las que) siento gratitud → “things (for which) I feel gratitude”

Why is it por and not para in por las que?

Here, por expresses cause / reason: gratitude for something.

Some common patterns:

sentir gratitud por algo – to feel gratitude for something
estar agradecido por algo – to be grateful for something

para is more for purpose, destination, or intended recipient:

Esto es para ti. – This is for you (recipient).
Estudio español para viajar. – I study Spanish in order to travel.

Since we mean gratitude for something, por is the correct preposition:
cosas por las que siento gratitud = “things for which I feel gratitude.”

Why is it las que and not just que, lo que, or las cuales?

All of these are relative forms, but they’re used differently:

las que
- Used when you have a specific antecedent with gender and number.
- cosas is feminine plural → las must also be feminine plural.
- tres cosas por las que… = “three things for which…”
que (without las)
- With some prepositions (like por), standard grammar prefers a preposition + article + que construction (por las que).
- In casual speech, many people do say cosas que estoy agradecido por, but it’s considered less formal / less neat.
lo que
- Used when the antecedent is abstract/unknown/unspecified, not a specific plural noun:
  - lo que siento = what I feel
  - por lo que siento gratitud = what I feel gratitude for (in general)
- It wouldn’t match cosas (plural, feminine), so it doesn’t fit here.
las cuales
- More formal equivalent of las que:
  - tres cosas por las cuales siento gratitud
- Correct, but sounds more formal or written; por las que is more neutral.

Could I say tres cosas de las que siento gratitud instead of por las que?

You might hear de las que in some contexts, but por las que is more natural here because:

The standard phrase is sentir gratitud por algo.
So por fits with the usual verb–preposition combination.

de las que tends to sound better with verbs or expressions that normally take de, e.g.:

cosas de las que me acuerdo – things I remember
cosas de las que estoy hablando – things I’m talking about

In this sentence, stick with por las que for idiomatic Spanish.

Could I say tres cosas por las que estoy agradecido instead of siento gratitud?

Yes, and that would actually sound very natural in Latin American Spanish:

tres cosas por las que siento gratitud – three things for which I feel gratitude
tres cosas por las que estoy agradecido – three things I am grateful for

Both are correct; the nuance:

sentir gratitud uses the noun gratitud (“gratitude”). Slightly more formal or reflective.
estar agradecido uses the adjective agradecido (“grateful”). Very common in everyday speech.

Also common:

tres cosas que agradezco – three things I’m grateful for (literally: that I thank)

All three versions are good; estoy agradecido and que agradezco are especially common in spoken Latin American Spanish.

Why use sentir here and not tener (like tengo gratitud)?

In Spanish, sentir is the normal verb for feelings and emotions:

siento gratitud – I feel gratitude
siento alegría / miedo / tristeza – I feel joy / fear / sadness

Using tener with gratitud (tengo gratitud) is either incorrect or sounds very unnatural.

So, for emotions:

Use sentir + [emotion noun]
- siento gratitud, siento amor, siento tristeza
Or estar + [emotional adjective]
- estoy agradecido, estoy triste, estoy feliz

Is gratitud a common word in Latin American Spanish, or does it sound very formal?

Gratitud is common and completely natural, but it can sound a bit more formal or introspective than estar agradecido.

Rough guide:

gratitud – like English gratitude: used in written language, reflections, personal growth contexts, but also in normal speech.
estar agradecido/a – “to be grateful”: very common in everyday conversation.
agradecimiento – “thankfulness, appreciation,” often in more formal contexts (speeches, letters).

In a journal context like this sentence, siento gratitud fits very well.

Is the whole sentence formal, neutral, or informal in tone?

The sentence is neutral and works in most contexts:

You could use it in a conversation, in a self-help book, in a class, or in a personal journal.
Vocabulary like siento gratitud leans slightly toward the reflective/serious side, but it’s not stiff or overly formal.

An even more casual version might be:

Cada noche escribo tres cosas por las que estoy agradecido.
Cada noche escribo tres cosas que agradezco.