Puella in speculo vultum suum et os parvum spectat.

Because puella is in the nominative singular, which is the case typically used for the subject.

So in this sentence:

• puella = the girl → subject
• spectat = looks at / examines

That gives you the basic core: The girl looks at ...

An English speaker often expects word order to show the subject, but in Latin, case endings do most of that work.

Because Latin word order is much more flexible than English word order.

English usually needs:

• The girl looks at her face in the mirror.

Latin can place words in different orders for emphasis or style:

• Puella in speculo vultum suum et os parvum spectat.

Putting the verb at the end is extremely common in Latin, especially in straightforward prose. So this sentence feels very natural.

Because in can take different cases depending on the meaning:

• in + ablative = in / on something, showing location
• in + accusative = into / onto something, showing motion toward

Here the meaning is location:

• in speculo = in the mirror

The girl is not moving into the mirror; she is seeing something in it. So Latin uses the ablative:

• speculo = ablative singular of speculum

Classical Latin has no articles like English the and a/an.

So:

• puella can mean girl, a girl, or the girl
• speculo can mean a mirror or the mirror
• vultum can mean a face or the face

Which one sounds best depends on the context and the translation already given.

This is one of the biggest differences from English: Latin often leaves definiteness unstated.

Spectat comes from spectare, meaning to look at, watch, or observe.

It is:

• 3rd person singular
• present tense
• so: she looks at / the girl looks at

It is a little stronger and more deliberate than simply videt (sees).
So spectat suggests that she is actively looking at her reflection.

Because vultum is the direct object of spectat, so it must be in the accusative singular.

• dictionary form: vultus = face, expression, countenance
• accusative singular: vultum

The adjective suum must agree with vultum in:

• gender: masculine
• number: singular
• case: accusative

So:

• vultum suum = her own face

This is a very common question.

In Latin, a possessive adjective agrees with the thing possessed, not with the possessor.

Here:

• the possessor is puella = feminine
• but the possessed thing is vultum = masculine accusative singular

So Latin uses:

• suum, not suam

Compare:

• puella matrem suam videt = the girl sees her mother
  • suam agrees with matrem (feminine accusative singular)
• puella vultum suum videt = the girl sees her face
  • suum agrees with vultum (masculine accusative singular)

Suus, sua, suum is the reflexive possessive adjective. It refers back to the subject of the clause.

So in this sentence:

• puella ... vultum suum ... spectat
• literally: the girl looks at her own face

The her belongs to the girl herself.

This is different from a non-reflexive idea like someone else’s face.
Latin uses suus when the possessor is the subject.

Because os here is a neuter third-declension noun, and neuter nouns have an important pattern:

• nominative singular = accusative singular

So:

• os can be both mouth as subject and mouth as object

In this sentence it is a direct object, but it still appears as os.

That can feel strange to an English speaker, but it is completely normal in Latin.

Because parvum agrees with os.

• os = neuter singular accusative
• parvum = neuter singular accusative of parvus

So:

• os parvum = small mouth

Again, the adjective must match the noun in:

• gender
• number
• case

They are related, but not exactly the same.

• vultus usually means face, facial expression, or countenance
• os usually means mouth, and sometimes more broadly the face or mouth area

In this sentence, the combination suggests the girl is looking at features of her appearance in the mirror:

• vultum suum = her face / countenance
• os parvum = her small mouth

So the sentence is slightly descriptive, not just repetitive.

Grammatically, suum directly modifies vultum.

So the phrase is literally:

• vultum suum = her face
• et os parvum = and a small mouth / and her small mouth

In context, a reader will naturally understand that the mouth is also hers, because it is part of the same description of what she sees in the mirror.

If Latin wanted to make both possessives explicit, it could repeat the possessive adjective. But often Latin does not repeat words when the meaning is already clear.

Because both are in forms that work as direct objects, and both are joined by et:

• vultum suum = direct object 1
• os parvum = direct object 2
• et = and

So the structure is:

• Puella = subject
• in speculo = where
• vultum suum et os parvum = what she looks at
• spectat = verb

In other words: she looks at both things.

Because et simply joins two equal elements, just like and in English.

Here it joins:

• vultum suum
• os parvum

So:

• vultum suum et os parvum = her face and small mouth

That is the most straightforward way to coordinate two nouns or noun phrases in Latin.

Yes, very often.

For example, Latin could say things like:

• Puella vultum suum et os parvum in speculo spectat.
• In speculo puella vultum suum et os parvum spectat.

The core meaning would stay the same, because the cases still show the relationships.

However, word order can affect emphasis:

• putting in speculo earlier may highlight the setting
• putting vultum suum earlier may highlight what she sees

So Latin word order is flexible, but not random.

Yes. Speculum means mirror.

It is related to the idea of looking:

• specere = to look
• spectare = to look at, observe
• speculum = mirror, something for looking

So there is a nice connection in the sentence:

• she spectat...
• ...in a speculo

That kind of related vocabulary is common in Latin.