Vultus puellae laetus matrem laetam facit.

The subject is vultus.

You can tell because:

• vultus is nominative singular here.
• The verb facit is third-person singular, so it matches a singular subject.
• The rest of the sentence shows what that subject does: it makes something happen.

So the basic skeleton is:

• vultus ... facit = the face/expression ... makes

Here puellae is genitive singular, meaning of the girl or the girl's.

So vultus puellae means:

• the girl's face/expression
• literally, the face/expression of the girl

A learner often notices that puellae could also be dative singular or nominative plural in other contexts. That is true. But in this sentence, the genitive makes the best sense because it clearly shows possession or relationship with vultus.

Because laetus agrees with vultus, not with puellae.

This is a very common point for English speakers. In Latin, an adjective agrees with the noun it describes in:

• gender
• number
• case

Here:

• vultus is masculine singular nominative
• so the adjective describing it must also be masculine singular nominative
• that gives laetus

Even though the face belongs to a girl, the word vultus itself is grammatically masculine, so the adjective must be masculine too.

The endings tell you.

• laetus is masculine singular nominative
• vultus is masculine singular nominative
• puellae is feminine, not masculine

So laetus can only agree with vultus here.

This is one of the most important habits in reading Latin: do not rely only on word order. Look at the endings and match words by agreement.

Because of the way facere works in this kind of sentence.

Here facit means makes in the sense of causes someone to be something. Latin often uses:

• an accusative object
• plus an accusative adjective describing the result

So:

• matrem = mother as the direct object
• laetam = happy, describing what the mother is made to be

Together, matrem laetam facit means:

• makes the mother happy

This is often called a predicate accusative or object complement construction.

Because of the verb facit.

If you just saw matrem laetam by itself, it could mean the happy mother in the accusative. But once it is used with facit, Latin naturally reads it as:

• object: matrem
• resulting state: laetam

So the meaning becomes:

• makes the mother happy

In other words, laetam is not just an ordinary descriptive adjective here; it tells you the condition the mother is brought into.

Because the adjective applies to two different nouns.

• laetus describes vultus: the girl's face/expression is happy
• laetam describes matrem: the mother becomes happy

So the sentence connects two related ideas:

1. there is a happy expression on the girl's face
2. that happy expression makes the mother happy

Latin uses different forms of the same adjective because the nouns are different in gender, case, and function.

Because Latin relies much more on endings than on position.

English usually needs a fairly fixed order, such as:

• subject + verb + object

Latin is freer because the endings show the job each word is doing.

In this sentence:

• vultus is the subject
• puellae is genitive
• matrem is the direct object
• laetam goes with matrem
• facit is the verb

So even if the words are not in an English-like order, the grammar is still clear.

This order also helps group the sentence into two meaningful parts:

• vultus puellae laetus = the girl's happy face/expression
• matrem laetam facit = makes the mother happy

Yes, to a large extent.

Because Latin marks grammatical relationships with endings, many rearrangements are possible, for example:

• Vultus laetus puellae matrem laetam facit
• Matrem laetam vultus puellae laetus facit

The core meaning would stay basically the same, though the emphasis or flow might change.

That said, not every order is equally natural in every context. Latin authors choose word order for style, emphasis, and rhythm, not randomly.

Classical Latin normally has no articles.

So a noun like vultus can mean:

• a face/expression
• the face/expression

and context tells you which is best.

The same is true for matrem:

• a mother
• the mother
• sometimes even her mother, depending on context

English has to choose an article, but Latin usually does not state one.

Vultus is a fourth-declension masculine noun.

Its basic meaning is something like:

• face
• expression
• look
• countenance

A detail that can confuse learners is that, without macrons, some fourth-declension forms can look alike in writing. But in this sentence, the grammar shows that vultus is nominative singular, not some other form, because:

• it matches laetus
• it works as the subject of singular facit

So here vultus is simply the singular subject: the face/expression.