Taberna contra bibliothecam stat, et discipula ibi chartam novam emere vult.

Because contra takes the accusative case. So contra bibliothecam means opposite the library or across from the library.

• bibliotheca = library
• bibliothecam = accusative singular of bibliotheca

This is one of those cases where a preposition controls the case of the noun after it.

Here contra means opposite or across from in a spatial sense.

A learner may first meet contra as against, and that is also a common meaning. But with places, it can mean:

• opposite
• facing
• across from

So Taberna contra bibliothecam stat means the shop is located opposite the library.

Stat comes from stare, meaning to stand. Latin often uses stare for buildings or objects that are standing in a place.

So:

• taberna est = the shop is
• taberna stat = the shop stands / is situated

In English we usually just say is, but Latin often prefers the more vivid stands for physical location.

Taberna is nominative singular. It is the subject of stat.

So in the first clause:

• taberna = the shop
• stat = stands

The thing doing the action of standing is the subject, so it is in the nominative.

Discipula is nominative because it is the subject of vult.

The second clause is:

• discipula = the student / schoolgirl
• vult = wants
• emere = to buy

The same person who wants is also the person who buys, so Latin does not need to repeat a separate subject for emere.

Ibi is an adverb meaning there or in that place.

Here it most naturally refers to the place just mentioned, probably the shop. So the sense is that the student wants to buy the paper there, at that location.

Because ibi is an adverb, it does not change its form.

Because it is the direct object of emere.

The student wants to buy what?
Answer: chartam novam

So both words are accusative singular feminine:

• chartam = paper / a sheet of paper
• novam = new

The adjective novam matches chartam in:

• gender: feminine
• number: singular
• case: accusative

That agreement is a basic rule in Latin adjectives.

Because it depends on vult.

Latin commonly uses a complementary infinitive after verbs like:

• vult = wants
• potest = is able
• debet = ought

So:

• vult emere = wants to buy

This works very much like English wants to buy.

Vult is the 3rd person singular present active indicative of velle, meaning to want.

So here it means:

• he wants
• she wants
• it wants

Since the subject is discipula, the meaning is she wants.

Latin often leaves subject pronouns out because the verb ending already tells you the person and number.

In vult, the ending shows 3rd person singular. Then discipula tells you who that person is.

So Latin does not need to say ea vult unless it wants special emphasis.

Latin word order is much freer than English word order because the endings show the grammatical relationships.

For example:

• Taberna contra bibliothecam stat
• Contra bibliothecam taberna stat
• Stat taberna contra bibliothecam

All of these could express roughly the same basic idea, though the emphasis may differ.

A few helpful observations:

• Latin often puts the verb near the end.
• Important or topical words may be placed earlier.
• English depends much more on word order, while Latin depends much more on endings.

Not always exactly. Charta can mean several related things, depending on context:

• paper
• a sheet of paper
• a page
• a document
• sometimes a letter

In this sentence, chartam novam emere most likely means buying new paper or a new sheet of paper, though the exact English wording depends on context.

Yes. Et means and, and here it joins two clauses:

1. Taberna contra bibliothecam stat
2. discipula ibi chartam novam emere vult

Each clause has its own main verb:

• stat
• vult

So this is a straightforward compound sentence.