In hac bibliotheca non satis spatii est, itaque quidam discipuli foris exspectant.

Because in with a place where something is located takes the ablative in Latin.

So:

• in hac bibliotheca = in this library
• bibliotheca is ablative singular here
• hac is also ablative singular feminine, agreeing with bibliotheca

A useful contrast is:

• in bibliotheca = in the library / inside the library (location, ablative)
• in bibliothecam = into the library (motion toward, accusative)

Here the sentence describes where the lack of space exists, so the ablative is used.

Because hac is the ablative feminine singular form of hic, haec, hoc.

Since bibliotheca is:

• feminine
• singular
• ablative

the demonstrative must match it:

• nominative: haec bibliotheca = this library
• ablative: hac bibliotheca = in this library

So hac is simply the correct agreeing form.

This is a very common Latin way to say there is not enough space.

Breakdown:

• non = not
• satis = enough
• spatii = of space
• est = there is

Literally, it is something like there is not enough of space.

In Latin, satis often takes a partitive genitive, and spatii is that genitive. So spatii does not mean space as a straightforward subject; it means of space after satis.

This is similar to other expressions like:

• multum aquae = much water / much of water
• parum temporis = too little time / too little of time
• satis pecuniae = enough money

So non satis spatii est is idiomatic Latin, even if the literal structure feels a little unusual in English.

Because it depends on satis as a partitive genitive.

The noun spatium is a neuter second-declension noun:

• nominative singular: spatium
• genitive singular: spatii

After words like satis, Latin often uses the genitive to show enough of what. So:

• satis spatii = enough space
• literally: enough of space

English usually does not say it that way, but Latin often does.

It is singular because the idea is there is not enough space, not spaces are not enough.

In this construction, spatii is not the subject; it is genitive after satis. The whole phrase behaves like a singular idea: enough space.

So Latin uses:

• non satis spatii est = there is not enough space

This is similar to English there is enough time, where the whole expression is treated as a single amount.

Itaque means and so, therefore, or so.

It connects the first clause to the second:

• In hac bibliotheca non satis spatii est = there is not enough space in this library
• itaque quidam discipuli foris exspectant = so some students are waiting outside

Its position is normal. Latin often places connecting words like itaque, igitur, or autem near the beginning of a clause, but not always as the very first word.

It means some students or certain students.

Quidam, quaedam, quoddam is an indefinite pronoun/adjective meaning something like:

• a certain
• certain
• some

Here it is masculine nominative plural to agree with discipuli:

• quidam discipuli = some students / certain students

It suggests an unspecified group, not all the students.

Because quidam and quidem are completely different words.

• quidam = a certain, some
• quidem = indeed, certainly, at least

So:

• quidam discipuli = some students
• quidem discipuli would not mean the same thing at all

A learner may confuse them because they look similar, but they have different grammar and different meanings.

Discipuli is nominative plural, and it is the subject of exspectant.

We know this because:

• exspectant is third person plural = they wait / are waiting
• the people doing the waiting are the students
• therefore discipuli must be nominative plural

So:

• quidam discipuli = some students
• exspectant = are waiting

Together: some students are waiting

Here foris is an adverb meaning outside or outdoors.

So:

• foris exspectant = they are waiting outside

This is useful to distinguish from similar forms:

• foris = outside, outdoors
• foras = out, to the outside

A simple way to remember it:

• foris often expresses location
• foras often expresses motion outward

In this sentence the students are already outside, so foris is appropriate.

Because Latin word order is much freer than English word order.

English usually prefers:

• some students are waiting outside

Latin can arrange the words differently for style, emphasis, or rhythm:

• quidam discipuli foris exspectant

Putting the verb at the end is extremely common in Latin, especially in straightforward prose. It often gives the sentence a neat, balanced finish.

Yes, exspectant is present tense, third person plural.

It can be translated in either of these ways depending on context:

• they wait
• they are waiting

Latin present tense often covers both the simple present and the present progressive of English.

So quidam discipuli foris exspectant can naturally mean:

• some students wait outside
• some students are waiting outside

In normal English, are waiting sounds more natural here.

Its basic meaning is library, and that is clearly the right meaning here.

Depending on context, bibliotheca can sometimes refer more specifically to:

• a collection of books
• a bookcase
• a library room

But in this sentence, since people are inside and some students must wait outside because there is not enough space, library is the natural meaning.

Because Latin does not need a dummy subject like English there.

English says:

• there is not enough space

But Latin simply says:

• non satis spatii est
• literally: not enough of space is

Latin often uses est by itself where English uses there is. This is normal and very common.