Mi abuela brasileña frena antes del cruce ciclista.

In standard Spanish, you normally use a possessive adjective like mi directly before the noun:

• mi abuela = my grandmother
• tu abuela = your grandmother
• su abuela = his/her/your grandmother

Unlike English, Spanish does not usually combine this with the in this kind of phrase, so la mi abuela is not normal standard Spanish.

In Spanish, most descriptive adjectives usually come after the noun.

So:

• abuela brasileña = Brazilian grandmother

This is the normal order. Putting the adjective before the noun is sometimes possible in Spanish, but it often changes the tone or emphasis, and with nationalities it normally goes after the noun.

Because adjectives in Spanish usually agree with the noun in gender and number.

Here, abuela is:

• feminine
• singular

So the adjective must also be feminine singular:

• brasileña = feminine singular
• brasileño = masculine singular
• brasileñas = feminine plural
• brasileños = masculine plural

So:

• mi abuela brasileña
• mi abuelo brasileño

Frena is the third-person singular present indicative form of frenar.

That means it matches subjects like:

• él frena = he brakes
• ella frena = she brakes
• usted frena = you brake (formal)
• mi abuela frena = my grandmother brakes

So in your sentence, frena means brakes / slows to stop in the present tense.

Because de + el contracts to del in Spanish.

So:

• antes de el cruce ❌
• antes del cruce ✅

This contraction happens almost always with de + el.

A similar contraction happens with a + el = al:

• voy al parque

One important exception: if el is part of a proper name, you usually do not contract it:

• de El Salvador ✅

Cruce means crossing or intersection/crossing point, depending on context.

Ciclista here is describing the kind of crossing: a crossing related to bicycles or cyclists.

So cruce ciclista means something like:

• bicycle crossing
• cyclist crossing

That said, depending on the country, people might also say things like:

• paso ciclista
• cruce para ciclistas
• paso para bicicletas

So the phrase is understandable, but another expression may sound more natural in some regions.

Because ciclista is one of those words that often keeps the same form for masculine and feminine.

For people:

• el ciclista = the male cyclist
• la ciclista = the female cyclist

As an adjective, it also often stays the same:

• cruce ciclista
• ruta ciclista

So unlike brasileño/brasileña, ciclista does not need a different ending here.

Very often, yes.

When antes is followed by a noun, Spanish normally uses de:

• antes del cruce
• antes de la esquina
• antes de la salida

When it is followed by a verb, you usually get:

• antes de cruzar = before crossing
• antes de salir = before leaving

So in this sentence, antes del cruce ciclista is exactly what you would expect.

Usually, no, not in the same sense.

Frenar is commonly used without se when something or someone brakes:

• El auto frena
• Mi abuela frena

Adding se changes the structure and can sound unnatural here. For a simple meaning like brakes / slows down before the crossing, plain frena is the normal choice.

A rough pronunciation guide is:

• mi → mee
• abuela → ah-BWEH-lah
• brasileña → brah-see-LEH-nyah
• frena → FREH-nah
• antes del cruce ciclista → AHN-tehs del KROO-seh see-KLEES-tah

The letter ñ is pronounced like the ny sound in canyon.

So brasileña is approximately brah-see-LEH-nyah, not brah-see-LEH-na.

Sometimes, depending on context.

Frenar most directly means to brake or to slow by braking. In real-life English, though, people might translate it more naturally as:

• My Brazilian grandmother brakes before the bicycle crossing.
• My Brazilian grandmother slows down before the bicycle crossing.
• My Brazilian grandmother stops before the bicycle crossing.

The exact English choice depends on whether the action is just slowing down or coming to a full stop. Grammatically, though, the Spanish verb here is specifically frena.