Medica dicit puellam non graviter laborare.

Because after dicit Latin often uses an indirect statement construction.

In English, we say:

• The doctor says that the girl is not very ill

In Latin, instead of using that plus a normal finite verb, Latin usually uses:

• an accusative subject
  • an infinitive

So:

• puellam = the girl as the subject of the infinitive
• laborare = to be suffering / to be ill

That is why puellam is accusative rather than nominative.

This is also because of the indirect statement after dicit.

Latin commonly does this after verbs of saying, thinking, knowing, hearing, and similar verbs. Instead of saying:

• The doctor says that the girl is not very ill

Latin says, more literally:

• The doctor says the girl not seriously to be suffering

So laborare is infinitive because it is part of that indirect statement.

A direct statement would look different:

• Puella non graviter laborat = The girl is not very ill / is not suffering seriously

But once it becomes what someone says, Latin changes it to:

• puellam non graviter laborare

The subject of laborare is puellam.

Even though puellam is accusative, it is still the logical subject of the infinitive. In indirect statement, Latin uses:

• accusative noun/pronoun = subject of the infinitive
• infinitive = the verb of the reported statement

So in this sentence:

• medica = the one doing the saying
• puellam = the one who is supposedly not seriously ill
• laborare = what the girl is doing

Because Latin usually does not need one in this construction.

English says:

• The doctor says that the girl...

But Latin normally expresses this idea with the accusative-and-infinitive construction instead of a separate word meaning that.

So:

• dicit puellam laborare

already means:

• says that the girl is suffering

There is no missing word here; this is just standard Latin grammar.

Non negates the idea of laborare in the indirect statement.

So:

• puellam non graviter laborare

means that the girl is not suffering seriously / not very ill.

Because non is placed before graviter, it naturally negates the whole phrase graviter laborare. In effect, the meaning is:

• not seriously suffering
• not being seriously ill

Latin word order is flexible, so non does not always have to stand right next to the main verb.

Graviter is an adverb, meaning seriously, severely, or gravely.

It describes how the girl is suffering.

So:

• laborare = to suffer / to be ill
• graviter laborare = to suffer seriously / to be seriously ill

The adverb graviter comes from the adjective gravis meaning heavy, serious, or severe.

Yes, that is a very reasonable question.

Laborare basically has the idea of to labor, to toil, to struggle, or to suffer. Depending on context, it can mean different things in English, including:

• to work
• to struggle
• to suffer
• to be troubled
• to be ill

In this sentence, because the speaker is a doctor (medica) and the adverb is graviter (seriously), the most natural sense is something like:

• to be ill
• to be suffering
• to be seriously unwell

So context helps determine the best English meaning.

It is a present infinitive.

In indirect statement, the tense of the infinitive shows time relative to the main verb, not necessarily absolute time by itself.

Here:

• dicit = says (present)
• laborare = present infinitive

That combination usually means the action of laborare is happening at the same time as the saying.

So the sense is:

• The doctor says that the girl is not seriously ill
• or ... is not suffering seriously

If Latin wanted to show an earlier action, it would usually use a perfect infinitive instead.

Because medica is the subject of dicit.

So the structure is:

• medica = the female doctor / the doctress / simply the doctor if the doctor's sex matters
• dicit = says

That means medica is the person speaking, so it must be nominative singular.

Yes. Medica is the feminine form, corresponding to masculine medicus.

So if the sentence uses medica, Latin is presenting the doctor as female.

Depending on context, English might translate it as:

• the female doctor
• the woman doctor
• or just the doctor, if the translator does not want to emphasize sex

But grammatically, the Latin form is feminine.

Yes. Latin word order is much more flexible than English word order because the endings show the grammar.

For example, these would mean essentially the same thing:

• Medica dicit puellam non graviter laborare.
• Medica puellam non graviter laborare dicit.
• Puellam medica non graviter laborare dicit.

The exact order can affect emphasis or style, but the core grammar stays the same because:

• medica is nominative
• puellam is accusative
• laborare is infinitive

So Latin does not rely as heavily on word order as English does.

Because that would be a direct statement, not a reported one.

Compare:

• Puella non graviter laborat.
  = The girl is not very ill.

But if you want to say:

• The doctor says that the girl is not very ill

Latin usually changes the reported statement into indirect statement:

• Medica dicit puellam non graviter laborare.

So the change from puella ... laborat to puellam ... laborare is exactly what Latin normally does after dicit.

Yes. Dicit is third person singular present active.

It matches medica, which is singular:

• medica dicit = the doctor says

If the subject were plural, the verb would also be plural:

• medicae dicunt = the female doctors say

So the verb ending helps confirm that medica is one person.

Very literally, it would be something like:

• The female doctor says the girl not seriously to suffer

That sounds unnatural in English, but it shows the Latin structure clearly:

• Medica = the doctor
• dicit = says
• puellam = the girl (accusative subject of infinitive)
• non graviter = not seriously
• laborare = to suffer / to be ill

A natural English translation is smoother, but the literal version helps explain the grammar.