Mater cum eo de epistula loquitur.

Because loquitur comes from loquor, loqui, locutus sum, which is a deponent verb.

Deponent verbs look passive in form, but they have an active meaning. So:

• loquitur = he/she speaks or is speaking
• not is spoken

This is one of the first things learners notice in this sentence, because in many Latin verbs -tur would suggest a passive meaning, but with loquor it does not.

Loquitur is third person singular present indicative.

That means it goes with a singular subject such as:

• he
• she
• it
• or a singular noun like mater

So in this sentence, mater is the subject, and loquitur means she speaks / she is speaking / she talks.

Latin often does not need an expressed subject pronoun, because the verb ending already tells you the person and number.

Here, loquitur already tells you:

• third person
• singular

So Latin does not need to add a separate word for she. The noun mater makes the subject explicit anyway.

English usually needs a subject pronoun or noun, but Latin can leave it out if the verb ending makes it clear.

Because mater is the subject of the sentence, so it is in the nominative case.

The basic idea is:

• mater = nominative singular = mother as the subject
• matrem = accusative singular = mother as a direct object

Since the mother is the one doing the action of speaking, Latin uses mater.

Eo is ablative singular of is, ea, id (he / she / it, or that depending on context).

The preposition cum means with, and it takes the ablative case. So:

• cum eo = with him

That is why Latin uses eo, not is.

A learner might expect is, but is is nominative; after cum, you need the ablative form eo.

Because de takes the ablative case.

So:

• epistula can be nominative singular or ablative singular in form
• after de, it must be understood as ablative singular

Thus:

• de epistula = about the letter / concerning the letter

If it were epistulam, that would be accusative, and de does not take the accusative.

It means about the letter or concerning the letter.

In Latin, de often means:

• about
• concerning
• sometimes from/down from, depending on context

Here the context with loquitur makes about the natural meaning:

• de epistula loquitur = she is talking about the letter

No. Cum eo means with him, not to him.

That tells you the mother is speaking in his company / in conversation with him, not directing speech to him in the same way Latin might express with another construction.

In practice, English may say she is talking with him or she is talking to him, but the Latin here literally uses with him.

Yes. Latin word order is much more flexible than English word order because the case endings show the grammatical relationships.

This sentence could be rearranged in various ways without changing the core meaning, for example:

• Mater de epistula cum eo loquitur
• Cum eo mater de epistula loquitur
• De epistula mater cum eo loquitur

The chosen order may affect emphasis or style, but the endings still show what each word is doing.

The dictionary form is loquor.

A full dictionary entry is often given as:

• loquor, loqui, locutus sum

This shows that it is a deponent verb and gives its principal parts. From that entry, you learn that loquitur is one present-tense form of the verb.

Usually epistula means letter, especially in an introductory sentence like this one.

Depending on context, it can mean:

• a written letter
• an epistle
• a message in literary or formal contexts

But for most learners, letter is the best basic meaning here.

By itself, eo could theoretically mean him or it, because it is the ablative singular form of is, ea, id.

Context decides the most natural translation. If the meaning shown to the learner is with him, then the context clearly points to a male person.

So grammatically eo could be more than one thing, but in this sentence the intended meaning is clear from context.

Either can be correct.

Latin present tense often covers both:

• simple present: speaks
• progressive present: is speaking

So Mater cum eo de epistula loquitur can be understood as:

• Mother speaks with him about the letter
• Mother is speaking with him about the letter

Which English version is best depends on context and style.