Learn Hardcore Spanish (Spain): Mi amigo mexicano estudia español en la universidad. - My Mexican friend studies Spanish at the university.

Because amigo is singular here, the possessive must also be singular: mi amigo. If you had several Mexican friends, you would say Mis amigos mexicanos.

Why is there no subject pronoun like él? Why not Él mi amigo mexicano estudia… or Él estudia…?

In Spanish, subject pronouns (like yo, tú, él, ella) are often omitted because the verb ending already shows the subject.

estudia is the he/she/it or usted form of estudiar in the present tense.
The subject is clear from context: mi amigo mexicano is doing the action.

So:

Mi amigo mexicano estudia español… = Él estudia español…, but with the subject phrase spelled out.
Saying Él mi amigo mexicano estudia… is incorrect; you don’t put él directly in front of the noun like that.

You could say Él estudia español en la universidad, but then you lose the extra info mi amigo mexicano.

Why is the adjective mexicano after amigo? Could I say mi mexicano amigo?

Most descriptive adjectives in Spanish go after the noun:

amigo mexicano = Mexican friend
universidad pública = public university

So mi amigo mexicano is the normal order.

You could technically say mi mexicano amigo, but it sounds marked or poetic, and in everyday Spanish it would be unusual or might suggest a different nuance (e.g. emphasizing “Mexican” in a literary way). Stick to mi amigo mexicano.

Why is it mexicano and not mexicana?

Adjectives must agree in gender and number with the noun they describe.

amigo is masculine singular → adjective must be masculine singular: mexicano
amiga (female friend) is feminine singular → mexicana

Examples:

Mi amigo mexicano = my (male) Mexican friend
Mi amiga mexicana = my (female) Mexican friend
Mis amigos mexicanos = my (male or mixed group) Mexican friends
Mis amigas mexicanas = my (all female) Mexican friends

What is the difference between amigo and amiga?

Both mean friend, but they mark grammatical gender:

amigo = male friend
amiga = female friend

In mixed or unknown-gender groups, amigos is usually used in standard Spanish:

Mis amigos can mean “my friends” (all male, or mixed).

If you specifically want “female friends,” you say mis amigas.

Why is español not capitalized? In English, Spanish is capitalized.

In Spanish:

Names of languages and nationalities are written with lowercase:
- español, inglés, mexicano, español (as an adjective).
Names of countries are capitalized:
- México, España, Estados Unidos.

So español is correctly written with a lowercase e in estudia español.

Why is it estudia and not está estudiando like he is studying?

Spanish uses the simple present much more than English does.

Mi amigo mexicano estudia español… can mean:
- He studies Spanish (in general, as a fact/habit)
- He is studying Spanish (this year/these days, as an ongoing action)

Está estudiando español emphasizes right now / at the moment a bit more, but in many contexts Spanish prefers the simple present where English uses is studying.

So estudia is the natural choice for a general fact like “He studies Spanish at university.”

Why is it en la universidad and not a la universidad?

Different verbs use different prepositions:

estudiar en = to study at / in (a place)
→ Estudia español en la universidad.
ir a = to go to
→ Va a la universidad. = He goes to the university.

So:

Estudia en la universidad = He studies at the university.
Va a la universidad = He goes to the university.

The preposition depends on the verb.

Why do we say la universidad and not un universidad or el universidad?

Two points: gender and definiteness.

Gender:
universidad is a feminine noun → it must take la or una:
- la universidad (the university)
- una universidad (a university)
  El universidad is grammatically wrong.
Definiteness / typical usage:
When talking generally about someone’s institution (school, university, church) in Spanish, the definite article is common:
- en la universidad ≈ “at university / at the university” (in general, not necessarily a specific one in contrast to others).

You can say en una universidad if you mean “at some (unspecified) university,” but the original sentence treats it as his known place of study, so la universidad is natural.

Why is there no article before español? Why not el español?

Both are possible, but they have slightly different tendencies:

Estudia español.
Very common, especially when talking about studying the language in general; sounds natural and neutral.
Estudia el español.
Also correct, but can sound a bit more formal, or like focusing on the language as a subject or object: “He studies the Spanish language.”

In everyday speech when you mean “He’s learning/studying Spanish (as a language)”, estudia español (without article) is more usual.

What is the infinitive form of estudia, and how is it conjugated?

The infinitive is estudiar (to study).

Estudia is:

3rd person singular, present indicative: él/ella/usted estudia

Some forms of estudiar in the present:

yo estudio – I study
tú estudias – you study (informal singular)
él / ella / usted estudia – he / she / you (formal) study
nosotros / nosotras estudiamos – we study
vosotros / vosotras estudiáis – you all study (informal plural, used in Spain)
ellos / ellas / ustedes estudian – they / you all study

In the sentence, estudia agrees with mi amigo mexicano (he).

Can I say Mi amigo mexicano estudia castellano instead of español?

In Spain, both español and castellano can refer to the Spanish language.

español – the most international, neutral term for the Spanish language.
castellano – often used in Spain (and some other regions) to refer to Spanish, especially in contrast with other languages spoken in Spain (Catalan, Galician, Basque).

So in Spain, Mi amigo mexicano estudia castellano en la universidad is possible and understandable, though with a slight regional/terminological nuance. español is always safe and standard.

What is the difference between mi and mío, and why do we use mi here?

Both relate to my, but they are used differently:

mi = my (before a noun, no article):
- mi amigo, mi casa, mi coche
mío / mía / míos / mías = mine (possessive pronoun or stressed possessive, often after a noun or with an article):
- un amigo mío = a friend of mine
- La casa es mía. = The house is mine.

In Mi amigo mexicano…, we need my directly before the noun, so we use mi, not mío.