La enfermedad cambió su vida.

Cambió is the preterite form of cambiar for él/ella/usted: he/she/it changed.

In this sentence, the illness is presented as something that changed the person’s life as a completed event or clear turning point.

• La enfermedad cambió su vida = The illness changed his/her life
• La enfermedad cambia su vida would mean changes/is changing
• La enfermedad cambiaba su vida would suggest an ongoing or habitual past action, which sounds less natural here

So cambió is the normal choice if you mean a definite change in the past.

The accent mark shows both pronunciation and verb form.

• cambio = I change / change or change as a noun
• cambió = he/she/it changed

The accent tells you the stress goes on the last syllable: cam-bió.

Without the accent, it would be read differently and would no longer be the same tense/person.

Su can mean several things in Spanish:

• his
• her
• your (formal singular)
• their

So su vida could mean:

• his life
• her life
• your life (formal)
• their life

Spanish often leaves this ambiguous unless the context makes it clear. If needed, Spanish can clarify:

• la vida de él = his life
• la vida de ella = her life
• la vida de usted = your life
• la vida de ellos/as = their life

It agrees with the thing owned, not with the owner.

Here, vida is singular, so you use su.

Compare:

• su vida = his/her/your/their life
• sus vidas = his/her/your/their lives

Notice that su does not change depending on whether the owner is male or female. That is why su can be ambiguous.

Spanish uses the definite article much more often than English.

Here, la enfermedad can mean:

• the illness when referring to a specific illness already understood from context
• sometimes more generally illness/disease as a concept, depending on context

In Spanish, it is very normal to include the article with nouns where English might not. So La enfermedad cambió su vida is completely natural.

Yes. La enfermedad is the subject, and cambió is the verb.

A quick way to see that is to ask: What changed his/her life?
Answer: La enfermedad.

So the structure is:

• La enfermedad = subject
• cambió = verb
• su vida = direct object

Because su vida is a thing, not a person.

Spanish uses the personal a before a specific human direct object, for example:

• Veo a María = I see María

But here:

• cambió su vida

su vida is not a person, so there is no personal a.

Yes — and that is actually a very common and natural way to say it in Spanish.

• La enfermedad cambió su vida
• La enfermedad le cambió la vida

The second version uses:

• le = to him / to her / to you (formal)
• la vida instead of su vida

Spanish often prefers this structure with body parts, personal belongings, and things closely connected to a person.

So both are correct, but le cambió la vida can sound especially idiomatic.

Yes, Spanish word order is more flexible than English, although the original order is the most neutral here.

The basic sentence is:

• La enfermedad cambió su vida

Other versions are possible depending on emphasis, for example:

• Su vida cambió por la enfermedad = focuses more on his/her life
• La vida le cambió por la enfermedad is less natural in this exact sense
• La enfermedad le cambió la vida is very natural

So the original sentence is a clear, standard way to say it, but Spanish does allow alternatives.

A simple pronunciation guide is:

la em-fer-me-DAD cam-BYÓ su BEE-da

A few helpful notes:

• enfermedad is stressed on the last syllable: -dad
• cambió is stressed on -bió
• v in vida sounds closer to a soft Spanish b
• su is short and unstressed

In Spain, the pronunciation of c does not affect this sentence, because there is no ce or ci here.

The dictionary form is cambiar, which means to change.

Here is the relevant pattern in the preterite:

• yo cambié
• tú cambiaste
• él/ella/usted cambió
• nosotros/as cambiamos
• vosotros/as cambiasteis
• ellos/ellas/ustedes cambiaron

So cambió is the third-person singular preterite form of cambiar.