Clamor puerorum matrem terret.

Because clamor is in the nominative singular, which is the case normally used for the subject of a sentence.

You can also confirm this by looking at the verb terret, which is third-person singular: he/she/it frightens. A singular verb needs a singular subject, and clamor fits that role.

So the basic structure is:

• clamor = subject
• matrem = direct object
• terret = verb

Because puerorum is in the genitive plural.

The noun is puer, pueri = boy. Its genitive plural ending is -orum, so puerorum means of the boys.

Here it depends on clamor:

• clamor puerorum = the shouting/noise of the boys
• more naturally in English: the boys' shouting or the boys' noise

Because matrem is accusative singular, the case commonly used for the direct object.

It comes from mater, matris = mother. The accusative singular form is matrem.

So:

• mater = subject form
• matrem = object form

In this sentence, the mother is the one being frightened, so she is the direct object of terret.

Terret is:

• third person
• singular
• present tense
• active voice
• indicative mood

It comes from terreo, terrere = frighten, terrify.

So terret means:

• he frightens
• she frightens
• it frightens

In this sentence, the subject is clamor, which is grammatically singular, so terret means frightens.

Because puerorum is not the subject.

A very common beginner mistake is to notice the plural noun and assume the verb should agree with it. But Latin verbs agree with the subject, not just with any nearby noun.

Here:

• clamor = subject, singular
• puerorum = genitive modifier, plural
• terret = singular verb, agreeing with clamor

So the sentence means that the noise/shouting frightens the mother, not that the boys do.

Because Latin has no articles.

There is no separate word for the or a/an in ordinary Latin. English has to add them when translating.

So clamor puerorum matrem terret could be translated as:

• The boys' shouting frightens the mother
• A shout of the boys frightens a mother
• The noise of the boys frightens the mother

Which one is best depends on context. In a simple classroom sentence, The boys' shouting frightens the mother is the most natural.

Yes. Latin word order is much freer than English word order because the endings show each word's job in the sentence.

So these could all mean basically the same thing:

• Clamor puerorum matrem terret.
• Matrem clamor puerorum terret.
• Puerorum clamor matrem terret.
• Terret matrem clamor puerorum.

The core meaning stays the same because:

• clamor is still nominative
• puerorum is still genitive
• matrem is still accusative
• terret is still the verb

What changes is mainly emphasis or style, not the basic meaning.

Not here.

Puerorum is genitive, so it means of the boys, not by the boys.

If Latin wanted to say by the boys with a passive verb, it would usually use ab plus the ablative, for example ab pueris.

So:

• puerorum = of the boys
• ab pueris = by the boys

In this sentence, puerorum tells you whose clamor it is.

Clamor can mean things like:

• shout
• cry
• uproar
• noise
• shouting

In this sentence, the most natural English is probably:

• the boys' shouting
• the noise of the boys

So clamor does not have to mean one single shout; it can also suggest noisy commotion or loud shouting.

They are:

• clamor, clamoris = shout, noise
• puer, pueri = boy
• mater, matris = mother
• terreo, terrere = frighten

These dictionary forms help you identify the declension or conjugation and explain the endings you see in the sentence:

• clamor = nominative singular
• puerorum = genitive plural
• matrem = accusative singular
• terret = third-person singular present active

A very literal translation would be:

The noise of the boys frightens the mother.

A more natural English translation is:

The boys' shouting frightens the mother.

Both reflect the same Latin structure:

• clamor = noise/shouting
• puerorum = of the boys
• matrem = the mother
• terret = frightens