Discipuli discendi causa ante meridiem in bibliothecam veniunt, non solum legendi causa, sed etiam disputandi causa.

Discendi causa means for the sake of learning or more naturally to learn.

Literally:

• discendi = of learning
• causa = for the sake of

So Latin uses a pattern:

gerund in the genitive + causa

This is a very common way to express purpose. English often uses to learn, but Latin often prefers discendi causa.

Yes. Discendi is a gerund, from the verb discere (to learn).

A gerund is a verbal noun. In this sentence, discendi is the genitive singular form of the gerund.

You can think of it as meaning something like:

• of learning

Latin gerunds are often used in oblique cases, especially in expressions of purpose like:

• discendi causa = for the sake of learning
• legendi causa = for the sake of reading
• disputandi causa = for the sake of discussing

So although it comes from a verb, here it functions as a noun.

Because in this idiom, causa usually comes after the genitive.

So Latin normally says:

• discendi causa
• legendi causa
• disputandi causa

rather than putting causa first.

This is a fixed and very common expression. It may help to memorize it as a unit:

genitive + causa = for the sake of ...

Because in can take different cases depending on whether it shows motion or location.

• in + accusative = into / to a place, showing motion
• in + ablative = in / inside a place, showing location

Here the students are coming to the library, so there is movement toward it:

• in bibliothecam veniunt = they come into/to the library

If the sentence were describing where they are, Latin would use the ablative:

• in bibliotheca sunt = they are in the library

Bibliothecam is accusative singular.

It is accusative because it follows in in the sense of motion toward a place:

• in bibliothecam = into the library / to the library

The noun is bibliotheca, bibliothecae (first declension), so:

• nominative singular: bibliotheca
• accusative singular: bibliothecam

Ante meridiem literally means before midday.

More naturally, in English, it means:

• before noon
• in the morning

Meridiem is accusative singular, because ante takes the accusative.

So:

• ante = before
• meridiem = midday / noon

This is also the same phrase behind the abbreviation a.m. = ante meridiem.

Discipuli is the subject because:

1. It is in the nominative plural
2. The verb veniunt is third person plural
3. The two agree in number

So:

• discipuli = students
• veniunt = they come

That makes discipuli the natural subject: the students come.

Latin word order is much more flexible than English word order.

Placing the verb near the end is very common in Latin, especially in straightforward prose. The sentence can place other information first:

• who is acting: discipuli
• why: discendi causa
• when: ante meridiem
• where to: in bibliothecam
• finally the action: veniunt

So the ending veniunt gives the sentence a neat finish. This is normal Latin style, not something strange or poetic.

This is a very common correlative expression meaning:

not only ... but also ...

In this sentence:

• non solum legendi causa
• sed etiam disputandi causa

So the students come:

• not only for the sake of reading
• but also for the sake of discussing

It is a useful pattern to memorize:

• non solum X, sed etiam Y

Sometimes Latin also uses non modo ... sed etiam ... with a similar meaning.

It is repeated for clarity and balance.

The sentence says:

• non solum legendi causa
• sed etiam disputandi causa

Repeating causa makes the parallel structure very clear. It strongly marks that both phrases express purpose.

Latin could sometimes omit a repeated word if the meaning were obvious, but here the repetition is elegant and easy to understand. It also gives the sentence a nicely balanced rhythm.

Because the sentence is using the purpose expression with causa, which requires the genitive gerund, not the infinitive.

So Latin says:

• legendi causa = for the sake of reading
• disputandi causa = for the sake of discussing

The infinitive (legere, disputare) would not fit this construction.

English often prefers an infinitive:

• to read
• to discuss

But Latin often expresses the same idea with:

• gerund + causa

Yes. The sentence uses the same structure three times:

• discendi causa
• legendi causa
• disputandi causa

Each one is:

• a gerund in the genitive
• followed by causa

That repeated pattern helps you read the sentence more easily. Once you understand the first one, the next two work exactly the same way.

Bibliotheca is ultimately from Greek, but in Latin it behaves like a normal first-declension noun.

So for grammar purposes, what matters is simply that it declines like a regular first-declension feminine noun:

• bibliotheca
• bibliothecam
• bibliothecae, etc.

Its origin is interesting, but it does not make the grammar harder here.

Yes. Latin has several ways to express purpose, but gerund + causa is one of the clearest and most common.

Other purpose constructions include:

• ad
  • accusative of a gerund/gerundive
• a supine in some contexts
• a purpose clause with ut

But in this sentence, discendi causa, legendi causa, and disputandi causa are elegant and very standard.

For a learner, the key point is:

• gerund + causa = for the sake of doing something = in order to do something