Learn Hardcore Latin: Hodie magistra in schola discipulos docet. - Today the female teacher teaches the students in the school.

Latin does not have separate words for “the” or “a/an” (articles).
Nouns like magistra, schola, discipulos can mean “teacher / the teacher / a teacher” depending on context.
So magistra can be translated as “the teacher” or “a teacher”, whichever makes better sense in English.
The meaning is carried by context and endings, not by articles.

How do we know that magistra is the subject and discipulos is the object?

Latin uses case endings to show a noun’s role in the sentence.

magistra ends in -a, which here is the nominative singular ending of a 1st-declension noun → normally subject.
discipulos ends in -os, which is the accusative plural ending of a 2nd‑declension masculine noun → normally direct object.
So even though discipulos comes right before the verb, the endings tell us:
magistra = the one doing the teaching; discipulos = the ones being taught.

What does the ending -os in discipulos tell us exactly?

The ending -os on discipulos indicates:

case: accusative (direct object)
number: plural (more than one)
gender: masculine (from the dictionary form discipulus)

So discipulos means “students” specifically as the direct object: (someone) teaches the students.

Why is it in schola and not in scholam?

Latin in can take either the ablative or accusative, with different meanings:

in + ablative (here: in schola) = in / on / at (location, where something happens).
in + accusative (e.g. in scholam) = into / onto (motion toward a place).

In this sentence, the teacher is already at/in school while teaching, so Latin uses in schola (location, ablative).

What case is schola, and how do we know?

schola is in the ablative singular after the preposition in.
For 1st‑declension nouns like schola, the nominative and ablative singular can both end in -a.
We know it is ablative here because the preposition in with the meaning “in / at” must be followed by the ablative.
So in schola = “in/at school”.

Does magistra specifically mean a female teacher?

Yes.
The basic Latin word for teacher is magister (masculine).
The feminine form magistra is used for a female teacher.
If the teacher were male, the sentence would be: Hodie magister in schola discipulos docet.

How do we know that docet means “teaches” in the present tense?

The verb docet comes from docēre (“to teach”).
The ending -t is the standard 3rd person singular present active ending: he/she/it [does something].
So docet = “he/she teaches” (right now, generally, or habitually), not “taught” or “will teach.”
Context gives us the natural English translation “teaches” or “is teaching.”

Why does docet come at the end of the sentence? Can it go somewhere else?

Latin word order is quite flexible because endings show each word’s function.
A very common pattern is to place the verb last, so docet at the end is typical.
You could also say Magistra hodie discipulos in schola docet or Hodie magistra discipulos in schola docet, and the basic meaning stays the same.
Changing the order mainly affects emphasis and style, not the basic grammar.

Can hodie (today) go in a different position in the sentence?

Yes. Hodie is an adverb, and adverbs can move around fairly freely.
You might see:

Magistra hodie in schola discipulos docet.
Magistra in schola hodie discipulos docet.

All of these mean essentially “Today the teacher teaches the students in school.”
Placing hodie first can slightly emphasize “today”.

How would the sentence change if the students were the ones teaching the teacher?

We would swap the cases (subject vs. object):

Students as subject: discipuli (nominative plural)
Teacher as object: magistram (accusative singular, feminine)

A straightforward version would be:
Hodie discipuli magistram in schola docent. = “Today the students teach the teacher in school.”
Note that the verb also changes from docet (he/she teaches) to docent (they teach).

Do we need a preposition like “to” or “for” in front of discipulos?

No.
Latin usually doesn’t use a preposition for a direct object.
Instead, it uses the accusative case, which is already shown by the ending -os in discipulos.
So magistra discipulos docet literally is “the teacher teaches students”, without an extra word for “to” or “for.”

Is in schola closer to English “in the school” or “at school”?

It can be translated either way, depending on context and natural English:

“in the school” stresses being inside the building.
“at school” is more general and often sounds more natural in English.

Latin in schola itself just expresses location at/in school; it does not force one nuance over the other.

How would you say “Today the teacher teaches the good students in school”?

You add an adjective agreeing with discipulos in case, number, and gender:

bonus, -a, -um = good
Accusative masculine plural (to match discipulos) is bonos.

So the sentence is:
Hodie magistra in schola discipulos bonos docet.
= “Today the teacher teaches the good students in school.”