La muerte cambió todo.

Spanish often uses the definite article with abstract nouns more than English does. So la muerte can mean death as a general concept, where English would usually drop the article.

In context, la muerte could mean:

• death in general
• the death of someone/something specific, if the context makes that clear

So even though English often says Death changed everything or Death changes everything, Spanish naturally says La muerte...

Because muerte is a feminine noun in Spanish, so it takes la.

You have to learn noun gender as part of the word:

• la muerte
• una muerte
• la muerte rápida, not el muerte rápido

Its gender is grammatical, not biological. Since death is not a person, feminine here does not mean female.

Cambió is the preterite tense, third person singular, from cambiar.

So:

• cambiar = to change
• cambió = changed

The preterite is used for a completed action in the past. Here it presents the change as a finished event:

• La muerte cambió todo. = Death changed everything.

If you used the imperfect instead, cambiaba, it would suggest an ongoing or repeated past action, which would not fit this sentence as naturally.

The accent mark shows where the stress falls: cam-bió.

It also helps distinguish it from cambio:

• cambio = I change / change as a noun in some contexts
• cambió = he/she/it changed

So the accent is both a pronunciation guide and a meaning distinguisher.

Here todo means everything.

In Spanish, todo can work in different ways:

• todo = everything
• todo el día = all day
• todos los libros = all the books

In La muerte cambió todo, there is no noun after todo, so it means everything.

Because of the sentence structure and the verb form.

In La muerte cambió todo:

• la muerte = the thing doing the action, so it is the subject
• cambió = changed
• todo = the thing affected by the action, so it is the direct object

So the structure is:

Subject + verb + object
La muerte + cambió + todo

That is the same basic order as Death changed everything in English.

Yes. Depending on context, la muerte can be understood as:

• death in a general or dramatic sense
• the death of a particular person

If the surrounding context is about one specific death, then The death changed everything may be the most natural English interpretation.

If the sentence is more general, literary, or philosophical, Death changed everything may fit better.

Spanish often leaves out subject pronouns because the verb ending already gives enough information.

Here, cambió tells you the subject is:

• he changed
• she changed
• it changed
• or a noun like la muerte

Since la muerte is already stated, there is no need to add a pronoun. In fact, adding one would usually sound unnecessary.

Yes. Muerte is the noun related to morir.

• morir = to die
• la muerte = death

This is like:

• to live and life
• to die and death

The forms look quite different, so it is worth learning them together.

Yes, but it would mean something slightly different in focus.

• La muerte cambió todo. = Death changed everything.
  Focus: death was the cause.

• Todo cambió. = Everything changed.
  Focus: the result, not the cause.

So both are correct, but they are not interchangeable in every context.

A simple pronunciation guide is:

la MWER-te kam-BYÓ TO-do

A few notes:

• muerte sounds roughly like MWER-te
• cambió is stressed on the last syllable: kam-BYÓ
• todo is TO-do

In Spain, the c in cambió is a hard k sound because it comes before a. So it is kam-, not a th or s sound.

La muerte cambió todo is a very normal, neutral word order in Spanish.

It simply states:

• subject: la muerte
• verb: cambió
• object: todo

Spanish can move words around more than English for emphasis, but this version is the most straightforward and natural one for a plain statement.