In cenaculo supra tabernam puella scribit, dum mater in solario vestes siccat.

Because in takes the ablative when it means in, on, at and shows location.

• in cenaculo = in the upstairs room
• in solario = in the terrace / sunny upper area

If there were motion into those places, Latin would normally use the accusative instead:

• in cenaculum = into the upstairs room
• in solarium = onto/into the terrace area

So here the ablative shows that both people are already in those places.

Because supra usually takes the accusative when used as a preposition meaning above or over.

So:

• taberna = nominative singular
• tabernam = accusative singular

In supra tabernam, the accusative is required by supra. The phrase means above the shop and further describes where the cenaculum is.

It works as one larger location phrase:

• in cenaculo = in the upstairs room
• supra tabernam = above the shop

Together, they mean something like in the upstairs room above the shop.

So supra tabernam is giving extra information about cenaculo.

Yes, English usually begins with the subject, but Latin has much freer word order.

Latin often places words according to emphasis, rhythm, or what the speaker wants to set first. Here the sentence begins with the place:

• In cenaculo supra tabernam = setting the scene first

Only then do we get:

• puella scribit = the girl is writing

So the Latin word order is natural, even though it is less like normal English order.

You know from the case and the clause structure.

• puella is nominative singular, so it can be the subject of scribit
• mater is also nominative singular, so it can be the subject of siccat

The sentence has two clauses:

1. In cenaculo supra tabernam puella scribit
2. dum mater in solario vestes siccat

Each nominative noun goes with the verb in its own clause.

Also, both verbs are third person singular:

• scribit = she writes / is writing
• siccat = she dries / is drying

Because vestes is the direct object of siccat.

• siccat = dries
• What does the mother dry? vestes = clothes

That is why vestes is accusative plural.

Its dictionary form is vestis, and its accusative plural is vestes.

Yes, it can stand on its own.

In Latin, as in English, to write does not always need an expressed object. It can simply mean:

• she is writing
• she writes

The object may be unknown, unimportant, or understood from context.

So puella scribit is a complete and natural clause.

Here dum means while.

It introduces an action happening at the same time as the action in the main clause:

• puella scribit = the girl is writing
• dum mater ... siccat = while the mother is drying clothes

The present tense in both clauses shows simultaneous action in a simple way. This is very common with dum.

Because Latin has no articles.

Latin does not have separate words for:

• the
• a / an

So a noun like puella can mean:

• the girl
• a girl

The exact sense comes from the context. The same is true for mater, tabernam, vestes, and the other nouns in the sentence.

Yes, they are strongly connected with Roman life.

• taberna = a shop, stall, or commercial room
• cenaculum = an upstairs room, upper apartment, or sometimes a dining room upstairs
• solarium = a terrace, flat roof space, or sunny upper area

So the sentence paints a very Roman-looking domestic scene: a girl writing in an upstairs room over a shop, while her mother dries clothes in an upper outdoor or sunny area.

Because Latin often likes to place the verb toward the end of the clause, though this is not a strict rule.

Here we get:

• setting or location first
• then the subject
• then the verb

So:

• In cenaculo supra tabernam puella scribit
• dum mater in solario vestes siccat

This feels very normal in Latin prose. English usually wants the verb earlier, but Latin often delays it.

The comma helps modern readers, but it is not something ancient Latin depended on in the same way modern English does.

The comma here simply marks the division between:

• the main clause: In cenaculo supra tabernam puella scribit
• the subordinate clause: dum mater in solario vestes siccat

So it is useful for reading, but the grammar itself does not depend on the comma.