Pater timet ne puer neglegens volumen suum iterum in horto relinquat.

In a clause after a verb of fearing, Latin works differently from English.

• timet ne ... = he fears that ... / he is afraid that ...
• timet ut ... = he fears that ... not / he is afraid that ... will not ...

So in this sentence:

• Pater timet ne puer ... relinquat
  = The father fears that the boy may leave...

This feels backward to English speakers at first, but it is a standard Latin pattern with verbs like timeo.

Because it is in a subordinate clause after a verb of fearing.

Latin normally uses the subjunctive in these fear clauses:

• timeo ne ...
• vereor ne ...
• metuo ne ...

So relinquat is not indicative because Latin treats the action as something feared, not simply stated as a fact.

The main verb is timet (he fears), which is present tense, so Latin normally uses primary sequence.

That is why the subordinate verb is present subjunctive:

• timet ... relinquat

The present subjunctive here usually refers to an action that is:

• happening at the same time, or
• still in the future relative to the fearing

So the sense is roughly he fears that the boy may leave / will leave.

Puer is nominative singular because it is the subject of relinquat.

Even inside a subordinate clause, Latin still uses the nominative for the subject of a finite verb:

• puer ... relinquat = the boy leaves / may leave

The word ne does not change puer into some other case. It simply introduces the fear clause.

Neglegens is modifying puer.

It is a present participle used adjectivally, and here it means something like:

• careless
• being careless
• careless as usual, depending on context

It agrees with puer in:

• case: nominative
• number: singular
• gender: masculine

So:

• puer neglegens = the careless boy or the boy, being careless

Because the book belongs to the subject of its own clause, namely puer.

Latin uses suus, -a, -um for a reflexive idea:

• volumen suum = his own book

Here the subject of the subordinate clause is puer, so suum refers back to puer.

If Latin used eius, that would normally refer to someone else’s book, not the boy’s own book.

This is a very important distinction:

• puer volumen suum relinquit = the boy leaves his own book
• puer volumen eius relinquit = the boy leaves his/hers/someone else’s book

Volumen is accusative singular, the direct object of relinquat.

It looks the same as the nominative because it is a neuter third-declension noun. For many neuter nouns in Latin:

• nominative singular = accusative singular

So:

• nominative: volumen
• accusative: volumen

Even though the form is the same, the function here is clear from the sentence: it is the thing being left behind.

Because in with the ablative usually means in or on in the sense of location.

• in horto = in the garden

Compare:

• in horto = in the garden where something is
• in hortum = into the garden movement toward

Here the idea is location, not motion, so Latin uses the ablative.

Iterum is an adverb meaning again, and it modifies relinquat.

So the sense is that the boy may leave the book in the garden again.

It is not modifying puer or volumen. It tells us how often the action happens or is expected to happen.

Latin word order is much more flexible than English word order because Latin relies heavily on inflected endings to show each word’s job in the sentence.

So Latin can say:

• Pater timet ne puer neglegens volumen suum iterum in horto relinquat

with the main idea still clear from the forms:

• pater = subject of timet
• puer = subject of relinquat
• volumen = object of relinquat
• in horto = location

Also, Latin often places the verb near the end of its clause, so relinquat naturally comes late.

Yes. Latin often places the verb at or near the end of a clause, especially in more regular prose style.

Putting relinquat last lets the sentence build toward the feared action:

• Pater timet ne puer neglegens volumen suum iterum in horto relinquat

That is a very normal Latin arrangement. It is not the only possible order, but it is a natural one.

It can suggest either, depending on context.

A present participle like neglegens may be understood as:

• a fairly permanent characteristic: careless
• a temporary state: being careless

In many beginner-level sentences, the easiest understanding is simply the careless boy. But grammatically it still carries a verbal flavor, so the boy, being careless is also possible.

Grammatically, yes, a different noun for book could have been used. But volumen specifically refers to a scroll or rolled-up written work in classical Latin.

So if your course translates it simply as book, that is fine for understanding, but the Roman object imagined by the Latin word is often more like a scroll than a modern bound book.

There are two different verbs, so there are two different subjects:

• Pater is the subject of timet
• puer is the subject of relinquat

So the structure is:

• The father fears
• that the boy may leave...

This is a useful thing to notice in Latin, because each finite verb has its own subject, even inside subordinate clauses.