Mi madre es peruana.

Because mi without an accent means my.

• mi madre = my mother
• mí with an accent means me after a preposition, as in para mí (for me)

So in this sentence, the correct form is mi.

In Spanish, when talking about someone’s nationality, you usually do not use an article.

So Spanish says:

• Mi madre es peruana.

Not:

• Mi madre es una peruana. ← this sounds unusual in a neutral statement

This is normal with nationalities:

• Es mexicana.
• Soy colombiano.
• Somos chilenos.

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

Nationality is one of the classic uses of ser, so:

• Mi madre es peruana. = nationality

Using estar here would be incorrect.

Because peruana agrees with madre, which is feminine.

In Spanish, nationality words often change form to match gender:

• peruano = masculine
• peruana = feminine

Since madre is feminine, you say:

• Mi madre es peruana.

Even if the speaker is male, the adjective still matches mother, not the speaker.

Usually no. In Spanish, nationalities are normally written in lowercase.

So:

• peruana ✅
• Peruana ❌ in normal usage

This is different from English, where Peruvian is capitalized.

Spanish often leaves out subject pronouns when they are already clear from the verb or context.

So instead of saying:

• Ella es peruana

you can simply say:

• Es peruana

And in your full sentence:

• Mi madre es peruana

the subject is already clear, so ella is not needed.

Yes, if the context already makes it clear that ella refers to your mother.

• Mi madre es peruana. = more explicit
• Ella es peruana. = She is Peruvian

Both are correct, but they are used in slightly different contexts.

Yes, you can say mamá too.

• Mi madre es peruana. = a bit more neutral or formal
• Mi mamá es peruana. = more common in everyday speech

In much of Latin America, mamá is very natural in conversation.

A simple approximate pronunciation is:

mee MAH-dreh ess peh-roo-AH-nah

A few notes:

• mi sounds like mee
• madre has a light tapped r
• peruana is pronounced roughly peh-roo-AH-nah
• The stress in peruana falls on ua: pe-ru-A-na

Here it works as an adjective describing nationality.

It agrees with the subject:

• Mi madre es peruana.

But words for nationalities can also sometimes act like nouns in other contexts. For example:

• La peruana habló primero. = The Peruvian woman spoke first.

In your sentence, though, it is best understood as a nationality adjective after ser.

Yes, but Mi madre es peruana is the most natural and basic order.

You might also hear:

• Peruana es mi madre — possible, but unusual and very marked
• Mi mamá es peruana — same basic structure, more everyday

For a beginner, the standard pattern to remember is:

[possessive] + [family member] + [ser] + [nationality]

There is a useful pattern. Many nationality adjectives ending in -o change to -a for feminine:

• peruano / peruana
• mexicano / mexicana
• chileno / chilena

Plural forms are:

• peruanos = masculine plural / mixed group
• peruanas = feminine plural

So yes, memorize the base form, but also learn how it changes for gender and number.

Yes, completely natural.

A speaker in Latin America would understand Mi madre es peruana immediately. In casual conversation, many people might say Mi mamá es peruana, but your original sentence is perfectly correct and natural.