Soror dicit agnum statim balaturum esse, si grex discesserit.

The sentence breaks down like this:

• Soror dicit = the main clause, The sister says
• agnum statim balaturum esse = an indirect statement, literally that the lamb is going to bleat at once
• si grex discesserit = a conditional clause, if the flock has left / leaves

So the core pattern is:

subject + verb of saying + accusative subject + infinitive

That is one of the most important Latin patterns to recognize.

Because it is the subject of the infinitive esse, not the subject of dicit.

After verbs of saying, thinking, knowing, perceiving, and similar verbs, Latin often uses the accusative-and-infinitive construction for indirect statement.

So:

• soror is nominative because she is doing the saying
• agnum is accusative because it is the subject inside the reported statement

In direct speech, you would expect agnus:

• Agnus statim balabit = The lamb will bleat at once

But in indirect speech after dicit, that becomes:

• dicit agnum statim balaturum esse

Because once the statement becomes indirect after dicit, Latin does not usually keep a finite verb there. Instead, it uses an infinitive.

Since the action is future relative to dicit, Latin needs a future infinitive, and that is formed with:

• future participle + esse

So:

• balaturum esse = to be about to bleat, or more naturally, will bleat

If the action were happening at the same time as dicit, Latin would normally use a present infinitive. If it were earlier, Latin would normally use a perfect infinitive.

Balaturum is the future active participle of balare, meaning to bleat.

Its form shows agreement with agnum:

• masculine
• singular
• accusative

That agreement matters because the future participle must match the subject of the infinitive in gender, number, and case.

So:

• agnum ... balaturum esse

means that the lamb is the one who will do the bleating.

Here discesserit is best understood as a future perfect indicative, even though its form is identical to the perfect subjunctive.

With si, Latin often uses the future perfect when one future action must happen before another future action.

So the sense is:

• if the flock has left
• more naturally in English, if the flock leaves

The idea is that the flock’s departure happens first, and then the lamb bleats.

That is why Latin uses discesserit rather than a simple future such as discedet.

You tell mainly from the context.

After si, a future condition often uses:

• future in the main clause
• future perfect in the si clause when the action is prior

That matches this sentence very well:

• the lamb will bleat
• if the flock has left / leaves

Also, nothing in the sentence strongly suggests a subjunctive idea such as uncertainty, purpose, or a contrary-to-fact condition. So the indicative reading is the natural one.

This is a common thing in Latin: one form can have more than one possible label, and context decides.

Yes. It goes with balaturum esse.

The sister is not simply saying two separate things. She is saying this whole idea:

• the lamb will bleat at once if the flock leaves

So the condition is part of what is being reported.

In other words, the direct version would be something like:

• Agnus statim balabit, si grex discesserit.

And the indirect version turns the main future verb into a future infinitive:

• Soror dicit agnum statim balaturum esse, si grex discesserit.

Grex is nominative singular, and it is the subject of discesserit.

So:

• grex = the flock
• discesserit = will have left / leaves

Even though a flock contains many animals, the noun itself is grammatically singular here, just like English the flock leaves can be singular.

Latin has no word exactly equivalent to the English articles a/an and the.

So agnum can mean:

• a lamb
• the lamb

Context tells you which is better in translation.

That is normal in Latin. The noun by itself does not mark definiteness the way English does.

Statim is an adverb meaning immediately, at once, or right away.

It modifies the idea of balaturum esse:

• agnum statim balaturum esse = that the lamb will bleat at once

Latin adverbs often stand near the word or phrase they modify, but Latin word order is flexible, so you should focus more on endings and structure than on strict English-style positioning.

Latin relies much more on inflected endings than on word order.

For example:

• soror is clearly the subject of dicit
• agnum is clearly accusative
• grex is clearly the subject of discesserit

Because those relationships are shown by form, Latin can arrange words more freely for emphasis, rhythm, or style.

So instead of forcing the sentence into English order, it is better to read by chunks:

• Soror dicit
• agnum statim balaturum esse
• si grex discesserit

That habit will make Latin much easier to process.

Not if the intended meaning is future.

A present infinitive such as balare would normally suggest action happening at the same time as the main verb of saying:

• dicit agnum balare = she says that the lamb is bleating / bleats

But this sentence means the bleating is still to come. So Latin uses the future infinitive:

• balaturum esse = will bleat

That distinction is very important in indirect statement.