Learn Hardcore Latin: Discipulus libros legit, ita mens eius non est tristis. - The student reads books, so his mind is not sad.

So Discipulus libros legit = “The student reads books.”
Latin has no article, so discipulus can be translated as “a student” or “the student” depending on context.

Why is it libros and not libri?

Both libri and libros come from liber, libri (m.) = “book.” The forms are different cases:

libri can be nominative plural (“books” as subject) or genitive singular (“of the book”)
libros is accusative plural, used for a direct object

In Discipulus libros legit:

discipulus = subject (who is doing the action)
libros = direct object (what is being read)

So it must be libros (accusative plural) because the student is reading books.

What tense and person is legit, and why does it look like another tense I’ve seen?

In this sentence, legit is:

Tense: present
Person: 3rd person
Number: singular

So it means “he/she/it reads” or “he/she/it is reading.”

The form legit is spelled the same as the 3rd person singular perfect (lēgit = “he/she read, has read”). They are distinguished by:

Pronunciation:
- present: legit (short e)
- perfect: lēgit (long ē)
Context: here, the context is clearly present-time: “The student reads books, so his mind is not sad.”

Latin often uses context (and vowel length, which is not usually written) to tell the forms apart.

Can the word order Discipulus libros legit be changed, and does it change the meaning?

Yes, Latin word order is relatively flexible. You could also see:

Discipulus legit libros
Libros discipulus legit
Libros legit discipulus

All of these basically mean “The student reads books.”

The core meaning (who does what to whom) is determined by endings (nominative discipulus, accusative libros), not by position in the sentence.

Word order mainly affects:

emphasis (for example, putting libros first might emphasize books)
style/rhythm

But the basic translation stays the same.

What does ita mean here, and how is it used?

Ita is an adverb meaning roughly:

“so”, “thus”, “in this way”, and by extension sometimes “therefore.”

In the sentence:

Discipulus libros legit, ita mens eius non est tristis.
“The student reads books, so his mind is not sad.”

Here ita links the two clauses and suggests a result or consequence: because he reads, thus his mind is not sad.

Related words:

sic – also “thus, so”, often interchangeable with ita
igitur, ergo, itaque – more clearly “therefore, so” as logical connectors

A more explicit “therefore” could have been itaque: Discipulus libros legit, itaque mens eius non est tristis.

What are mens and eius (case, gender, meaning)?

mens, mentis (f.) = “mind”
- Here: mens is nominative singular, the subject of non est tristis.
eius is the genitive singular of the 3rd-person pronoun is, ea, id
- Basic meaning: “of him / of her / of it / of that person”
- Here: “his” (referring to the student)

So mens eius literally = “the mind of him”, idiomatically “his mind.”

Why is it eius and not suus / sua / suum for “his”?

Latin has two different ways to say “his/her/its/their”:

Reflexive possessive adjective:
- suus, sua, suum = “his own, her own, its own, their own”
- Refers back to the subject of the same clause.
Non‑reflexive genitive of the pronoun:
- eius = “his / her / its” (singular)
- eorum / earum = “their” (plural)
- Refers to someone/something else, not the subject of that clause.

In ita mens eius non est tristis:

Subject of this clause = mens (the mind)
The possessor is the student (from the previous clause), not the subject mens itself

So Latin uses eius (“of him”) to show the mind belongs to that other person (the student), not to the subject mens as if it owned itself.

If you said mens sua, it would naturally mean “its own mind” with sua referring to mens as the subject, which is not what we want here.

Why is there no word for “the” or “a” before discipulus, libros, or mens?

Latin does not have articles like English “the” or “a/an.”

discipulus can be “a student” or “the student”
libros can be “books”, “the books”, or “some books”
mens eius can be “his mind” or “the mind of him”

Whether English needs “the” or “a” is decided from context, not from any explicit Latin word.

So we choose the most natural English rendering:
“The student reads books, so his mind is not sad.”

What is happening grammatically in non est tristis?

non est tristis breaks down as:

non = “not”
est = 3rd person singular present of esse = “to be” → “is”
tristis = adjective meaning “sad”

Grammatically:

est is a linking verb (copula)
tristis is a predicate adjective describing the subject (mens)
non negates the whole verb phrase

So mens eius non est tristis = “his mind is not sad.”
The adjective tristis is nominative singular feminine, agreeing with mens (also feminine nominative singular).

Could this also be understood as “The student's mind is not sad because he reads books”?

Yes, that is the idea in context, but it is expressed as a result/connection, not with an explicit word for “because.”

Literal structure:

Discipulus libros legit, ita mens eius non est tristis.
“The student reads books; thus his mind is not sad.”

English often prefers a causal translation here, so natural versions include:

“Because the student reads books, his mind is not sad.”
“The student reads books, so his mind is not sad.”

Latin could make the cause more explicit with quia or quod:

Mens eius non est tristis, quia discipulus libros legit.
- “His mind is not sad because the student reads books.”

In your sentence, ita leaves the connection slightly looser: “so / thus / as a result.”