Tum omnis domus gaudet, et mater patri de gemitibus puellae nocturnis narrat.

Because domus here is singular.

In this sentence, omnis domus means the whole household or the entire house as one unit. Since the noun is singular, the adjective modifying it must also be singular:

• omnis = whole / every (here: the whole)
• domus = house, home, household

So:

• omnis domus gaudet = the whole household rejoices

Even though a household contains several people, Latin treats domus as one singular noun here.

Domus is nominative singular here, because it is the subject of gaudet.

The verb gaudet means rejoices or is glad, and the subject is the thing doing that action:

• omnis domus = the whole household
• gaudet = rejoices

So domus must be nominative.

A learner may notice that domus is a slightly unusual noun, because it is a fourth-declension noun with some irregular features. But in this sentence, the important thing is simply that it is the nominative singular subject.

Because the grammatical subject is still singular: omnis domus.

Latin often uses a singular collective noun where English might think more in terms of a group of people. Here the idea is not all the people of the house rejoice as a plural subject, but the whole household rejoices as one collective unit.

So the verb is singular:

• domus gaudet = the household rejoices

If the subject were plural, the verb would be plural too.

Here it most naturally means the household, that is, the people belonging to the home.

Latin domus can mean:

• the physical house
• the home
• the household / family

Because gaudet describes an emotional response, domus here is best understood as the household rather than just the building.

So omnis domus gaudet is better understood as:

• the whole household rejoices

  rather than literally:

• the whole house rejoices

Because patri is the indirect object: the person to whom the mother tells something.

The verb narrare often works like this:

• someone narrat something
• alicui = to someone

So:

• mater patri ... narrat = the mother tells the father ...

Here:

• mater = nominative singular, the subject
• patri = dative singular, to the father

This is very similar to English tell someone something, except that Latin marks someone with the dative case.

Because the verb here uses de to mean about / concerning.

• de takes the ablative
• gemitibus is ablative plural

So:

• de gemitibus = about the groans

With narrare, Latin can express the topic of what is told by using de + ablative. In other words, the mother is telling the father about the girl's groans.

Gemitibus is ablative plural.

It is ablative because it follows de, and de always takes the ablative.

It is plural because the sentence refers to groans in the plural, not just one groan:

• gemitus = groan
• gemitibus = about the groans

So de gemitibus puellae nocturnis means about the girl's nightly groans.

Because puellae means of the girl.

It is a genitive singular, showing possession or association:

• gemitibus puellae = the girl's groans
• literally: the groans of the girl

This is a very common Latin use of the genitive. A noun in the genitive often answers the question whose?

So:

• de gemitibus puellae nocturnis = about the girl's nightly groans

Because nocturnis agrees in case, number, and gender with gemitibus, not with puellae.

Compare the forms:

• gemitibus = ablative plural masculine
• nocturnis = ablative plural masculine/feminine/neuter
• puellae = genitive singular feminine

So grammatically, nocturnis matches gemitibus, not puellae.

That means the phrase is:

• gemitibus nocturnis = nightly groans

not:

• puellae nocturnis = which would not match properly here

So the sense is the girl's nightly groans, not the nightly girl or anything like that.

Yes. Latin word order is fairly flexible because the endings show the grammar.

This order is perfectly normal, but other orders would also be possible. For example, Latin can move words around for emphasis or style. What matters most is the case endings:

• mater = subject
• patri = indirect object
• de gemitibus puellae nocturnis = prepositional phrase
• narrat = verb

A learner from English may expect a more fixed order, but Latin does not rely on position as much as English does.

This sentence has a clear and natural flow:

1. Tum omnis domus gaudet
2. et mater patri de gemitibus puellae nocturnis narrat

The verb narrat coming at the end is also very common in Latin prose.

Tum means then or at that time.

It helps connect this sentence to what came before in the story. It signals a next step in the narrative:

• first something happened
• tum = then
• now the whole household rejoices

So tum is not doing anything complicated grammatically; it is simply an adverb marking sequence in the story.

Because Latin, like English, often links related actions with et = and.

Here the two parts are closely connected:

• the whole household rejoices
• and the mother tells the father about the girl's nightly groans

Using et shows that these actions belong together in the same moment or scene.

Latin often uses simple coordination like this, especially in narrative prose. It is straightforward and idiomatic.