Post breve silentium omnes rursus laborare incipiunt, et magistra creta alba in tabula scribit.

Because post is a preposition that takes the accusative case when it means after.

So:

• post = after
• silentium = silence
• post silentium = after the silence / after a silence

In this sentence, breve silentium is the whole accusative phrase:

• breve = short
• silentium = silence

So post breve silentium means after a short silence.

Because the adjective has to agree with the noun it describes in gender, number, and case.

Here:

• silentium is neuter
• silentium is singular
• after post, it is accusative

So the adjective brevis, breve must also be:

• neuter
• singular
• accusative

That form is breve.

So:

• masculine/feminine nominative singular: brevis
• neuter nominative/accusative singular: breve

Since silentium is neuter, Latin uses breve.

Omnes is from omnis, meaning all or every.

Here it is being used by itself, without a noun, so it means something like:

• all (the people)
• everyone
• all of them

In the sentence, omnes is the subject of incipiunt:

• omnes ... incipiunt = all begin / everyone begins

Strictly speaking, omnes is plural, so Latin is saying all of them begin. English often translates that more naturally as everyone begins.

Because its subject, omnes, is plural.

• omnes = all of them
• incipiunt = they begin

So the verb must also be plural.

A quick breakdown:

• incipio = I begin
• incipis = you begin
• incipit = he/she/it begins
• incipiunt = they begin

Since omnes means all (the people/students), incipiunt is the correct form.

Because Latin often uses incipio + infinitive to mean begin to ...

So:

• laborare = to work
• incipiunt = they begin

Together:

• laborare incipiunt = they begin to work

This is very common in Latin. Compare:

• currere incipit = he begins to run
• legere incipiunt = they begin to read

So laborare is an infinitive complement after incipiunt.

Rursus is an adverb meaning again or back.

So:

• omnes rursus laborare incipiunt = everyone begins to work again

It modifies the verbal idea begin to work. Latin adverbs are often fairly flexible in position, so rursus can appear in a natural place without needing to stand exactly where English again would go.

Because Latin does not have to repeat pronouns like English does, and it can introduce a new subject simply by naming it.

The sentence has two coordinated clauses:

1. omnes rursus laborare incipiunt
2. et magistra creta alba in tabula scribit

The first clause has subject omnes. The second clause has subject magistra.

So the meaning is:

• everyone begins to work again,
• and the teacher writes on the board with white chalk.

The verb scribit is singular, which also matches magistra.

Because magistra is the feminine form of teacher.

• magister = male teacher
• magistra = female teacher

In this sentence, the teacher is female, so Latin uses magistra.

It is in the nominative singular because it is the subject of scribit.

Because this is an ablative of means or instrument: it tells you with what the teacher is writing.

So:

• creta = chalk
• alba = white

Together:

• creta alba = with white chalk

Latin often uses the ablative without a preposition for the tool or means by which something is done.

Examples:

• gladio pugnat = he fights with a sword
• penna scribit = he writes with a pen
• creta alba scribit = she writes with white chalk

So creta alba is not the direct object. It tells the instrument used.

Because the chalk is not what is being written; it is what the teacher is writing with.

If it were accusative, it would suggest chalk as a direct object. But here the real action is scribit = writes, and creta alba tells the means or instrument.

So:

• cretam albam would be accusative
• creta alba is ablative

This is why the phrase means with white chalk, not white chalk as an object.

Because in takes:

• ablative for location: in / on
• accusative for motion into / onto

Here the meaning is location:

• the teacher writes on the board

So Latin uses in tabula.

Compare:

• in tabula scribit = she writes on the board
• in tabulam aliquid ponit = she puts something onto the board

So the ablative shows place where, not motion toward.

Yes, in context it can.

The basic meaning of tabula is something like:

• board
• tablet
• plank
• writing surface

In a classroom context, in tabula scribit naturally means she writes on the board.

So this is a good example of how Latin words can have a range of related meanings, and context tells you which English word fits best.

Because Latin word order is more flexible than English word order. Latin relies mainly on endings, not position, to show how words function.

For example:

• magistra is clearly the subject because it is nominative
• creta alba is clearly ablative
• in tabula is a prepositional phrase
• scribit is the verb

So Latin can arrange them in a way that sounds natural or emphasizes certain parts:

• magistra creta alba in tabula scribit

English usually prefers a more fixed order:

• the teacher writes on the board with white chalk

Latin often places the verb later than English does, but many orders are possible.

Because Classical Latin has no articles.

So a noun like magistra can mean:

• a teacher
• the teacher

Likewise tabula can mean:

• a board
• the board

You decide from context which English article is best.

That is why:

• magistra becomes the teacher
• in tabula becomes on the board

even though Latin does not use separate words for the or a.

They are both present tense.

• incipiunt = they begin
• scribit = she writes

In a simple reading passage, the Latin present often describes actions happening now or as part of a narrated scene:

• after a short silence, everyone begins to work again,
• and the teacher writes on the board with white chalk.

So the sentence is in straightforward present-time narration.