Mi abuela es brasileña.

Mi means my.

It is the possessive adjective used before a singular noun:

• mi abuela = my grandmother
• mi hermano = my brother

Unlike English, mi does not change for masculine vs. feminine:

• mi abuelo = my grandfather
• mi abuela = my grandmother

It only changes in the plural:

• mis abuelos = my grandparents / my grandparents (grandfather and grandmother)
• mis abuelas = my grandmothers

Because abuela is the feminine form meaning grandmother.

Compare:

• abuelo = grandfather
• abuela = grandmother

The ending -a often signals a feminine noun, and -o often signals a masculine noun, though that pattern is not universal for every word in Spanish.

Because ser is used for identity, origin, nationality, and permanent or defining characteristics.

Here, es is the él/ella/usted form of ser:

• Mi abuela es brasileña. = My grandmother is Brazilian.

Nationality is treated as something you use ser for, not estar.

Compare:

• es brasileña = she is Brazilian
• está cansada = she is tired

So for nationality, ser is the correct verb.

Because the adjective has to agree with the noun it describes.

Since abuela is feminine singular, the nationality adjective is also feminine singular:

• abuela brasileña = Brazilian grandmother
• es brasileña = she is Brazilian

Compare the forms:

• brasileño = Brazilian (masculine singular)
• brasileña = Brazilian (feminine singular)
• brasileños = Brazilian (masculine plural or mixed group)
• brasileñas = Brazilian (feminine plural)

In Spanish, nationalities and languages are usually not capitalized.

So Spanish writes:

• brasileña
• mexicano
• argentina
• español

Even though English uses capitals for these words, Spanish normally does not.

After ser, when giving someone’s nationality, Spanish normally does not use an article.

So you say:

• Mi abuela es brasileña.

Not usually:

• Mi abuela es una brasileña.

Using una here would sound different and more marked, as if you were classifying or emphasizing her as a Brazilian woman rather than simply stating nationality.

Because in standard Spanish, a possessive adjective like mi usually replaces the article.

So you say:

• mi abuela
• mi madre
• mi casa

Not:

• la mi abuela

In modern standard Spanish, la mi... is not the normal pattern.

A simple pronunciation guide is:

mee ah-BWEH-lah es brah-see-LEH-nyah

A few key points:

• abuela has the stress on bue: a-BUE-la
• brasileña has the stress on le: bra-si-LE-ña
• ñ sounds like ny in canyon

So brasileña sounds roughly like brah-see-LEH-nyah.

Ñ is a separate letter in Spanish. It sounds like ny in words such as canyon.

So:

• brasileña ≈ brah-see-LEH-nyah

It is not the same as a plain n.

Compare:

• ano and año are different words
• n and ñ are different sounds in Spanish

Yes. That is also correct.

Compare:

• Mi abuela es brasileña. = My grandmother is Brazilian.
• Mi abuela es de Brasil. = My grandmother is from Brazil.

These are very close in meaning. The first uses a nationality adjective; the second uses de + country.

Both are common and natural.

You change the noun, the verb if needed, and the adjective to match.

Examples:

• Mi abuelo es brasileño. = My grandfather is Brazilian.
• Mis abuelos son brasileños. = My grandparents are Brazilian.
• Mis abuelas son brasileñas. = My grandmothers are Brazilian.

Notice the agreement:

• singular noun → singular adjective
• plural noun → plural adjective
• feminine noun → feminine adjective
• masculine noun → masculine adjective

Yes, but the normal, neutral order is:

• Mi abuela es brasileña.

Spanish can sometimes move things around for emphasis, but this basic order is the most natural for learners and the one you should use first.

It follows a very common pattern:

[possessive] + [noun] + [ser] + [adjective]

For example:

• Mi hermano es alto.
• Mi madre es mexicana.
• Mi profesora es simpática.