Puella pōmum rubrum matri ostendit.

Because puella is in the nominative case, which is the case usually used for the subject of the sentence.

• puella = the girl as the doer of the action
• She is the one who shows

So in Puella pōmum rubrum matri ostendit, puella is the one doing the showing.

Because pōmum is in the accusative case, which commonly marks the direct object.

The direct object is the thing directly affected by the verb. Here, the thing being shown is the red apple, so pōmum is the direct object.

• puella = the girl
• pōmum rubrum = the red apple

So the girl is showing the apple, not the other way around.

Because the adjective has to agree with the noun it describes in:

• gender
• number
• case

Here, pōmum is:

• neuter
• singular
• accusative

So the adjective ruber, rubra, rubrum becomes rubrum to match it.

That is why Latin says:

• pōmum rubrum = red apple

Even though both words end in -um, they are not the same kind of word:

• pōmum is a noun
• rubrum is an adjective agreeing with it

Because Latin uses the dative case for the indirect object, the person to whom something is given, told, shown, etc.

So:

• mater = mother
• matri = to/for the mother

In this sentence, the girl shows the apple to her mother, so matri is in the dative.

In this sentence:

• pōmum rubrum is the direct object: it is the thing being shown
• matri is the indirect object: she is the person to whom it is shown

A useful English pattern is:

• someone shows something to someone

So here:

• someone = puella
• something = pōmum rubrum
• to someone = matri

Classical Latin has no definite article (the) and no indefinite article (a/an) as normal separate words.

So:

• puella can mean girl, a girl, or the girl
• pōmum can mean apple, an apple, or the apple

The exact translation depends on context. In a simple teaching sentence, English often adds the or a to sound natural, but Latin itself does not include them.

Ostendit means shows or is showing, depending on context.

It comes from the verb ostendere, meaning to show.

In form, ostendit is:

• third person
• singular
• present tense
• active voice

So it means:

• he shows
• she shows
• it shows

Here, since the subject is puella, it means she shows.

The verb ending -t only tells you that the subject is third person singular: he, she, or it.

The verb itself does not tell you gender. We know it is she because the subject noun is puella, which means girl.

So:

• ostendit = he/she/it shows
• puella ostendit = the girl shows, so in English: she shows

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

In English, word order is very important:

• The girl shows the apple to the mother is different from
• The apple shows the girl to the mother

In Latin, the endings already tell you each word’s role:

• puella = subject
• pōmum rubrum = direct object
• matri = indirect object

So Latin can change the order without changing the basic meaning, for example:

• Puella pōmum rubrum matri ostendit
• Puella matri pōmum rubrum ostendit
• Pōmum rubrum puella matri ostendit

These all mean essentially the same thing, though the emphasis may change.

There is no special rule here saying it must be. Latin often places the verb at or near the end, but that is a tendency, not an absolute rule.

Putting matri before ostendit is perfectly natural Latin. It keeps the indirect object close to the verb:

• matri ostendit = shows to the mother

Another order would also be possible. The endings, not the position alone, show the grammar.

They come from different declensions:

• puella is first declension
• pōmum is second declension neuter
• mater is third declension

Their forms here are:

• puella = nominative singular
• pōmum = accusative singular
• matri = dative singular

This is a good example of how Latin uses different endings from different declensions to mark each word’s function.

Because neuter nouns in Latin have a special pattern:

• the nominative and accusative are always the same
• in the plural, nominative and accusative are also the same

So for pōmum:

• nominative singular: pōmum
• accusative singular: pōmum

You can still tell its role in the sentence from context and from the other words around it. Here, puella is clearly the subject, so pōmum must be the object.

The dictionary forms are usually:

• puella, puellae = girl
• pōmum, pōmī = apple, fruit
• ruber, rubra, rubrum = red
• mater, matris = mother
• ostendō, ostendere, ostendī, ostentum = show

Learners often need these dictionary forms because they help identify:

• the stem
• the declension or conjugation
• the possible meanings

Yes, macrons matter for vowel length, although many printed Latin texts leave them out.

With macrons:

• pōmum
• mātri would actually be wrong here; the correct form is matri with a short a
• ostendit

In this sentence, the only macron shown is in pōmum.

Macrons are useful because they help with:

• pronunciation
• meter in poetry
• distinguishing some forms from others

But even if a text writes pomum instead of pōmum, the meaning is still the same.

In a classroom-style Classical pronunciation, roughly:

• Puella = poo-EL-la
• pōmum = POH-mum
• rubrum = ROO-brum
• matri = MA-tree
• ostendit = os-TEN-dit

A fuller approximation of the whole sentence is:

poo-EL-la POH-mum ROO-brum MA-tree os-TEN-dit

Pronunciation varies somewhat depending on whether someone is using Classical, Ecclesiastical, or another restored system, but this is a good starting point.

Yes, the dative case can often be translated as to or for, depending on the verb and context.

With ostendere (to show), English usually says show something to someone, so to the mother is the most natural translation here.

But the important grammatical point is that matri is the dative singular and marks the person receiving the action indirectly.

Normally puella means girl. In some contexts it can refer more loosely to a young female person, and translation may vary a little depending on the situation.

But if Latin specifically wants to say daughter, the usual word is fīlia.

So in a basic sentence like this, puella should be understood simply as girl.