Ad forum ire nolo; immo in bibliotheca manere malo.

Because nolo and malo are followed by an infinitive.

• nolo = I do not want
• malo = I prefer / I would rather
• ire = to go
• manere = to remain / to stay

So:

• ire nolo = I do not want to go
• manere malo = I prefer to stay

This works very much like English I do not want to go and I prefer to stay.

Nolo means I do not want.

It is an irregular verb, historically from non volo.

Some useful forms are:

• volo = I want
• nolo = I do not want
• malo = I prefer / I want more

So in this sentence, ire nolo is literally to go I do not want.

Malo means I prefer or I would rather.

It is also irregular. It is related to magis volo, literally I want more.

So:

• manere malo = I prefer to remain
• more naturally in English: I would rather stay

It sets up a contrast with nolo:

• I do not want to go
• rather, I prefer to stay

Because ad means to / toward, and it takes the accusative case.

So ad forum means to the forum.

This is the normal way to express motion toward a place:

• ad forum = to the forum
• ad urbem = to the city
• ad amicum = to the friend / to a friend

Because the sentence is talking about staying in the library, not going to the library.

Latin often distinguishes:

• in
  • ablative = location, in / inside
• in
  • accusative = motion into

So:

• in bibliotheca = in the library (location)
• in bibliothecam = into the library (motion)

Since manere means to stay / remain, a location is needed, so in bibliotheca is correct.

Because the prepositions require different cases for different meanings.

• ad always takes the accusative
• in takes the ablative when it means in as a location

So:

• ad forum: motion toward a place → accusative
• in bibliotheca: location in a place → ablative

This is one of the most important Latin patterns to learn.

Because forum is a neuter second-declension noun.

For many neuter nouns in Latin, the nominative singular and accusative singular are identical.

So:

• nominative singular: forum
• accusative singular: forum

You know it is accusative here because it follows ad, and ad requires the accusative.

It is ablative singular.

The noun is bibliotheca, bibliothecae. In the first declension, the ablative singular ends in -a:

• nominative singular: bibliotheca
• ablative singular: bibliotheca

So although it looks the same as the nominative, its role is shown by the preposition in, which here takes the ablative.

Immo means something like no, rather, indeed rather, or on the contrary.

It is stronger than a simple but. It corrects or replaces the first idea with a better one.

So the sense is:

• I don’t want to go to the forum; rather, I prefer to stay in the library.

It gives the sentence a nice contrast.

You could use sed for a simple contrast, but immo is more pointed.

Compare the feel:

• sed = but
• immo = no, rather / in fact rather

So immo suggests not just contrast, but a correction or stronger alternative:

• not that option;
• rather this one.

That nuance fits well with nolo ... malo.

Because Latin usually does not need a separate subject pronoun.

The verb ending already tells you the subject:

• nolo = I do not want
• malo = I prefer

The -o ending shows first person singular.

Latin can include ego for emphasis, but it is not necessary:

• Ego ad forum ire nolo = I do not want to go to the forum

Without ego, the sentence is more neutral and normal.

Latin word order is more flexible than English word order, because the endings show the grammatical relationships.

This sentence is:

• Ad forum ire nolo; immo in bibliotheca manere malo.

A very literal order is:

• To the forum to go I do not want; rather in the library to remain I prefer.

That sounds strange in English, but it is perfectly normal in Latin.

The infinitive often comes before the main verb, especially with verbs like volo, nolo, and malo. The place phrases also come early for emphasis and clarity.

Yes. In many beginner sentences, manere is best translated as stay.

Depending on context, it can mean:

• remain
• stay
• continue to be

Here, stay in the library is probably the most natural English translation.

The semicolon shows a strong pause between two closely connected clauses.

The two halves are balanced:

• ad forum ire nolo
• immo in bibliotheca manere malo

Since the second half does more than merely continue the thought—it corrects or replaces it—the semicolon fits nicely. A comma could sometimes appear, but the semicolon makes the contrast clearer.

Yes, though they come from different backgrounds.

• forum is a very common Latin word meaning marketplace, public square, or forum
• bibliotheca is a Greek loanword meaning library

So the sentence uses normal vocabulary, though bibliotheca is a borrowed word that Latin speakers adopted.

Yes. Latin allows several alternatives, depending on style and emphasis. For example:

• Ad forum ire nolo, sed in bibliotheca manere malo.
• Nolo ad forum ire; immo malo in bibliotheca manere.

These mean essentially the same thing, but the emphasis shifts slightly with the word order and with sed versus immo.

The given sentence is perfectly good and very natural for a learner to study because it clearly shows:

• infinitives after nolo and malo
• motion toward a place with ad
  • accusative
• location with in
  • ablative
• contrast with immo