Magistra dicit vitia parva facile crescere, nisi statim corriguntur.

Because after a verb of saying like dicit, Latin very often uses indirect statement.

So instead of saying:

• The teacher says that small faults grow easily

Latin says, more literally:

• The teacher says small faults to grow easily

That is why you get:

• dicit = says
• crescere = to grow

A direct version would be Vitia parva facile crescunt.

In a Latin indirect statement, the subject of the infinitive goes into the accusative case.

So in:

• Magistra dicit vitia parva facile crescere

vitia parva is logically the subject of crescere, but grammatically it is put in the accusative because of the indirect statement construction.

This is often called the accusative-and-infinitive construction.

It is the subject of the infinitive crescere inside the indirect statement.

So:

• Magistra dicit = main clause
• vitia parva facile crescere = what the teacher says

Even though vitia parva is accusative in form, it still functions as the thing that is doing the growing.

Because parva agrees with vitia.

Here:

• vitia is neuter plural accusative
• parva is also neuter plural accusative

The adjective has to match the noun in gender, number, and case.

A useful reminder: neuter plural nominative and accusative often end in -a.

Facile is an adverb, meaning easily.

It modifies crescere:

• facile crescere = to grow easily

So facile is not describing vitia; it is describing how they grow.

Because the idea is unless they are corrected immediately, not unless they correct something.

So:

• corriguntur = they are corrected

It is passive because the faults are receiving the action.

Because its understood subject is vitia parva, which is plural.

Latin does not need to repeat the subject if it is already clear from the context. So in the nisi clause, the subject is still the same small faults.

That is why the verb is:

• corriguntur = they are corrected
• not corrigitur = it is corrected

Nisi means unless or if not.

It introduces an exception or condition:

• small faults grow easily, unless they are corrected immediately

So the basic idea is:

• they will grow easily
• except in the case where they are corrected at once

Yes. The understood subject is vitia parva.

Latin often leaves out a subject when it is obvious. English can do this less freely, so learners sometimes expect the noun to be repeated. Latin does not need to repeat it here.

So the clause is understood as:

• nisi vitia parva statim corriguntur

but Latin naturally leaves vitia parva unstated.

Because statim goes naturally with the verb and emphasizes the timing of the correction:

• statim corriguntur = are corrected immediately

Latin word order is more flexible than English word order. Position often helps with emphasis rather than simply marking grammatical function.

Here the placement makes immediately corrected feel like a tight unit.

The sentence expresses a general truth or general principle.

• dicit = says
• crescere = present infinitive, to grow
• corriguntur = are corrected

Latin often uses the present tense for statements that are generally true, not just for something happening at this exact moment.

It would be:

• Vitia parva facile crescunt, nisi statim corriguntur.

That helps show what changed:

• crescunt in direct statement
• crescere in indirect statement after dicit

This is a very useful way to understand the accusative-and-infinitive construction: first imagine the direct statement, then see how Latin converts it after a verb of saying.