Puer respondet: “Mihi umerus dolet.”

Mihi is the dative singular of ego.

With verbs like dolet, Latin often uses the person affected in the dative:

• mihi = to me / for me

So Mihi umerus dolet is literally something like To me, the shoulder hurts, which is the normal Latin way to express My shoulder hurts.

By contrast:

• ego = I (subject form)
• me = me (accusative or ablative, depending on use)

Neither of those fits this construction.

Because umerus is the subject of dolet.

Latin is structured here as:

• mihi = to me
• umerus = the shoulder
• dolet = hurts / is painful

So the thing that is hurting is the shoulder, which makes umerus nominative.

English usually says my shoulder hurts, where my marks possession. Latin often prefers:

• the body part as the subject
• the person affected in the dative

Latin often does not use a possessive adjective like meus when it is already obvious whose body part is meant.

Since mihi already means to me, Latin speakers can naturally understand that it is my shoulder.

So:

• Mihi umerus dolet = My shoulder hurts

If you said mihi umerus meus dolet, that would be more explicit, but usually unnecessary unless you want emphasis or contrast.

Dolet is the third person singular present active indicative of doleo, dolere.

Here it means:

• hurts
• aches
• is painful

Because the subject is umerus, the verb is third person singular:

• umerus dolet = the shoulder hurts

The same verb can also be used more generally for emotional pain or grief, depending on context.

The verb is singular because umerus is singular.

• umerus = shoulder
• dolet = hurts

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

• Mihi umeri dolent = My shoulders hurt

Latin verbs agree with their subject in number.

Yes, very much so.

This is a common and natural Latin pattern for physical discomfort:

• person affected in the dative
• body part in the nominative
• verb like dolet

So Latin often says something closer to:

• To me, the shoulder hurts rather than directly copying the English pattern:
• My shoulder hurts

This is one of those places where Latin and English organize the idea differently.

Yes. Latin word order is flexible.

You could also see:

• Umerus mihi dolet
• Dolet mihi umerus

The basic grammar stays the same because the endings show the roles:

• mihi is still dative
• umerus is still nominative
• dolet is still the verb

The order Mihi umerus dolet may put a slight emphasis on mihi, as if the speaker is saying My shoulder hurts or As for me, my shoulder hurts.

Respondet means he answers or he replies.

It is the third person singular present of respondeo, respondere.

So:

• Puer respondet = The boy replies / The boy answers

It introduces the direct speech that follows. In a story or dialogue, this is a very common way to set up what someone says.

Umerus can cover a range of related meanings, including:

• the shoulder
• the upper arm
• the shoulder area

In a sentence about pain like this, the usual natural meaning is shoulder.

English learners may notice the similarity to humerus, the bone name in English. That is related, but in ordinary Latin context umerus is not limited to the technical anatomical bone term.

In Latin, umerus is the classical spelling often taught in textbooks, though humerus is also found.

For a learner, the important point is that:

• umerus is a normal Latin word
• it is related to the English anatomical term humerus

So if you were surprised by the missing h, that is understandable. Latin spelling tradition is not always identical to the form familiar from English.

He could say doleo, but it would mean something broader like I am in pain or I am hurting, without naming the body part.

If he wants to specify where the pain is, Latin commonly uses the body part as the subject:

• Mihi umerus dolet = My shoulder hurts

So doleo is possible, but it does not express the same amount of information.