Mater fenestram claudit, ne ventus frigidus in cubiculum intret.

Because fenestram is the direct object of claudit: it is the thing being shut.

• fenestra = window
• fenestram = window in the accusative singular

Latin changes noun endings to show their job in the sentence. English usually relies more on word order.

Because mater is the subject of the sentence: she is the one doing the action.

Here the pattern is:

• Mater = mother as subject, so nominative
• fenestram = window as object, so accusative

Also, mater belongs to the 3rd declension, so its nominative singular is simply mater, not something ending in -a.

Because ne introduces a negative purpose clause.

So:

• ut = so that
• ne = so that ... not / lest

In this sentence, ne ventus frigidus in cubiculum intret means:

• so that the cold wind may not enter the room
• more naturally in English: to keep the cold wind from entering the room

By contrast, non usually just negates a word or statement, not a purpose clause.

Because it is in a purpose clause introduced by ne.

A very common Latin pattern is:

• ut + subjunctive = positive purpose
• ne + subjunctive = negative purpose

So:

• claudit is the main verb: she shuts
• intret is subjunctive because it expresses the intended result/purpose: so that ... may not enter

This is one of the most important uses of the Latin subjunctive.

Intret is:

• present
• subjunctive
• active
• 3rd person singular

from intrare = to enter

So literally it means may enter.

In this sentence, because of ne, it gives the sense may not enter or should not enter.

Because in takes different cases depending on meaning:

• in + accusative = into / motion toward
• in + ablative = in / inside / location

Here the wind would be moving into the room, so Latin uses the accusative:

• in cubiculum = into the room

If it meant in the room as a location, it would be in cubiculo.

Because ventus frigidus is the subject of intret.

Within the subordinate clause:

• ventus = wind
• frigidus = cold

Both are nominative singular masculine, and frigidus agrees with ventus.

So the clause means so that the cold wind may not enter the room.

Latin has no articles—no direct equivalent of the or a/an.

So a Latin noun like fenestra can mean:

• a window
• the window

The context tells you which English article sounds best.

That is why ventus frigidus can be translated as either:

• a cold wind
• the cold wind

depending on context.

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

English depends heavily on order:

• Mother shuts the window

Latin can move words around more freely because:

• mater is clearly the subject
• fenestram is clearly the object
• intret is clearly the verb of the subordinate clause

So Mater fenestram claudit is normal and clear, but other orders could also work.

Latin often places the verb at or near the end, especially in subordinate clauses, which is why intret comes last.

Yes. A very literal translation is:

• so that the cold wind may not enter the room

But in smoother English, you might say:

• to keep the cold wind from entering the room
• so the cold wind doesn’t come into the room

Latin often uses a purpose clause where English prefers an infinitive phrase like to keep...

Usually, yes. Cubiculum often means bedroom, sleeping room, or a more private room.

Depending on context, it may be translated more generally as room, but bedroom is often the most precise choice.

So in cubiculum could mean:

• into the bedroom
• or more generally, into the room

Because each verb has a singular subject:

• claudit matches mater = mother shuts
• intret matches ventus frigidus = the cold wind enters / may enter

In Latin, verbs change form to agree with their subjects in person and number.

So:

• claudit = he/she/it shuts
• intret = he/she/it may enter