Mater queritur de strepitu nocturno, quia infans dormire non potest.

Because queritur comes from queror, queri, questus sum, a deponent verb. Deponent verbs look passive in form, but they have an active meaning.

So:

• queritur = she complains
• not she is complained

This is very common in Latin, and it can feel strange at first to an English speaker.

Mater is the nominative singular, which is the case used for the subject of the sentence.

Here, mater is the one complaining, so nominative is correct.

A few forms of mater are:

• nominative: mater = mother
• accusative: matrem = mother as a direct object
• genitive: matris = of the mother

So mater queritur means the mother complains.

Because the verb queror is often used with de when you say what someone is complaining about.

So:

• queri de aliqua re = to complain about something

The preposition de takes the ablative case, so strepitus becomes strepitu.

That is why you get:

• de strepitu = about the noise

Because nocturno is an adjective agreeing with strepitu.

In Latin, adjectives must agree with the nouns they describe in:

• gender
• number
• case

Here:

• strepitu is masculine, singular, ablative
• so nocturno must also be masculine, singular, ablative

Together:

• de strepitu nocturno = about the nightly/nocturnal noise

Nocturnus, -a, -um means of the night, nightly, or nocturnal.

So strepitus nocturnus is a night noise or nocturnal noise. In this sentence, de strepitu nocturno means about the noise at night or about the nighttime noise.

Quia means because and introduces a clause giving the reason.

So the sentence structure is:

• Mater queritur... = the main statement
• quia infans dormire non potest = the reason why

In other words, the mother complains because the baby cannot sleep.

Because potest means is able or can, and after verbs like possum Latin normally uses an infinitive.

So:

• dormire = to sleep
• potest dormire = can sleep / is able to sleep
• non potest dormire = cannot sleep

If you said infans non dormit, that would mean the baby is not sleeping, which is a different idea. The Latin here expresses inability, not just the fact that sleep is not happening.

Because possum works with an infinitive, just like can in English is followed by a bare verb.

Compare:

• English: can sleep
• Latin: potest dormire

The infinitive dormire gives the action that the subject is able or unable to do.

Because its subject is infans, which is singular.

So:

• infans = the baby/infant
• potest = is able, can

If the subject were plural, Latin would use possunt:

• infantes dormire non possunt = the babies cannot sleep

It can be either, depending on the actual child. The noun infans, infantis can refer to a baby of either sex.

In this sentence, nothing in the grammar forces it to be specifically male or female. English infant or baby works well.

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

English depends heavily on word order:

• The mother complains because the baby cannot sleep.

Latin can move words around more freely:

• Mater queritur de strepitu nocturno, quia infans dormire non potest.

This order is natural and clear. Often Latin puts important ideas in noticeable positions, but the case endings and verb forms do most of the grammatical work.

Yes, Latin often places non directly before the word it negates, but there is some flexibility.

Here:

• infans dormire non potest

means the baby cannot sleep, with non negating potest.

You may also see:

• infans non potest dormire

That means the same thing. Both are understandable Latin.

The main dictionary forms are:

• mater, matris = mother
• queror, queri, questus sum = complain
• de = about, concerning
• strepitus, -us = noise, din
• nocturnus, -a, -um = nocturnal, nightly
• quia = because
• infans, infantis = infant, baby
• dormio, dormire, dormivi, dormitum = sleep
• possum, posse, potui = be able, can

This is useful because many of the forms in the sentence do not look exactly like their dictionary form.