Infans saepe sternuit, quia pulvis in cubiculo manet.

Infans is the nominative singular, and it is the subject of sternuit.

The noun infans, infantis is a third-declension noun meaning infant, baby, or young child. In this sentence, it is the one doing the sneezing, so it appears in the nominative case.

A useful thing to know is that infans can refer to either a male or female child; the form itself does not change here.

The ending -t shows that the verb is third person singular in the present indicative active:

• sternuō = I sneeze
• sternuis = you sneeze
• sternuit = he/she/it sneezes

Since the subject is infans = the infant/baby, Latin uses sternuit = sneezes.

Saepe is an adverb, meaning often.

It modifies the verb sternuit, telling us how often the infant sneezes.

Latin adverbs are often quite movable, so saepe could appear in slightly different places without changing the basic meaning. Here, placing it before sternuit is completely natural:

• Infans saepe sternuit = The infant often sneezes

Quia means because and introduces a causal clause.

So the sentence has two parts:

• Infans saepe sternuit = the main clause
• quia pulvis in cubiculo manet = the reason/cause

Latin commonly uses quia with the indicative when giving a straightforward reason, which is exactly what is happening here.

Pulvis is the subject of manet, so it must be in the nominative.

In the clause:

• pulvis = dust
• manet = remains / stays

So literally the Latin says something like:

• because dust remains in the room

Even if English might express this a little differently, grammatically pulvis is the thing doing the remaining/staying, so nominative is correct.

Because in with the ablative means in or inside a place where something already is.

• in cubiculo = in the bedroom/room

Latin uses:

• in + ablative for location: in the room
• in + accusative for motion into: into the room

So here there is no movement. The dust is already there, so Latin uses the ablative:

• cubiculo = ablative singular of cubiculum

Manet comes from maneō, which basically means remain, stay, or continue to be present.

So pulvis in cubiculo manet literally means:

• dust remains in the room

Depending on context, a smoother English translation might be:

• there is dust in the room
• dust stays in the room
• dust remains in the room

Latin often uses a verb like maneō where English might choose a different wording.

Classical Latin does not have articles like English the and a/an.

So:

• infans can mean an infant or the infant
• pulvis can mean dust, the dust, or sometimes some dust
• cubiculo can mean in a room or in the room, depending on context

You figure out which English article to use from the context and the intended meaning.

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

This sentence is:

• Infans saepe sternuit, quia pulvis in cubiculo manet.

But Latin could rearrange parts of it and still mean essentially the same thing, for example:

• Saepe infans sternuit, quia in cubiculo pulvis manet.

The original order is natural and clear:

• subject first: Infans
• adverb near the verb: saepe
• reason clause after the main clause: quia...

So yes, word order matters for emphasis and style, but not as rigidly as in English.

Cubiculo comes from cubiculum, cubiculī, a second-declension neuter noun meaning bedroom, chamber, or room.

Its ablative singular ending is -ō, so:

• nominative singular: cubiculum
• ablative singular: cubiculō (often written cubiculo without macrons)

Because it follows in expressing location, the ablative form is required.

Grammatically, infans is a noun of common gender, so it can refer to either a male or female infant.

The sentence itself does not tell you whether the baby is a boy or a girl. Latin often leaves that to context unless there is some reason to specify it.

So in translation, English might use:

• the infant
• the baby
• he
• she

depending on the surrounding context.

Both verbs describe what is happening as a general present situation:

• sternuit = sneezes
• manet = remains / stays

This makes good sense for a habitual or ongoing situation:

• the infant often sneezes
• because dust remains in the room

Latin present tense, like English present tense, can describe repeated actions or general facts, not just something happening at this exact second.