Mater unguentum labro pueri adhibet.

Here is the breakdown:

• mater = mother; nominative singular
• unguentum = ointment; accusative singular
• labro = to the lip; dative singular (same form as ablative singular)
• pueri = of the boy; genitive singular
• adhibet = applies; 3rd person singular, present active indicative

So the structure is basically:

• mater = subject
• unguentum = direct object
• labro pueri = to the boy’s lip
• adhibet = verb

Because mater is in the nominative singular, which is the case normally used for the subject of a sentence in Latin.

Also, the verb adhibet is 3rd person singular (he/she/it applies), so it matches a singular subject such as mater.

Because it is the direct object: it is the thing being applied.

In English, the direct object answers the question what?

• Mother applies what?
• ointment

So Latin puts unguentum in the accusative singular.

Because labro is not the direct object. The ointment is the direct object, not the lip.

The sentence means that the mother applies the ointment to the lip. Latin often uses the dative for the thing to which something is given, applied, or directed.

So:

• unguentum = the thing applied
• labro = the place/target to the lip

If the lip were the direct object, then you would expect labrum. But here it is not.

Because Latin often expresses ideas like to, for, or toward by using a case ending instead of a separate word.

Here, labro is in the dative singular, and that dative does the job that English expresses with to:

• labro = to the lip

So Latin does not need a separate preposition here.

Here pueri is genitive singular, meaning of the boy or the boy’s.

So:

• labro pueri = to the boy’s lip

The genitive is commonly used to show possession or belonging.

Yes, pueri can also be nominative plural, meaning boys. That is a very common thing for learners to notice.

But in this sentence, that reading does not fit well:

• the verb adhibet is singular, not plural
• mater is already a clear singular subject
• pueri sits naturally with labro as the boy’s lip

So here pueri is understood as genitive singular, not nominative plural.

A learner might wonder whether this could mean the boy’s mother applies ointment to the lip.

Grammatically, Latin sometimes allows that kind of ambiguity. But in this sentence, labro pueri is the most natural grouping:

• labro = to the lip
• pueri = of the boy

So together they make to the boy’s lip.

Word placement helps too: pueri comes right after labro, so it is naturally taken with it.

Still, this is a good example of how Latin readers often rely on context as well as endings.

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

English depends heavily on position:

• Mother applies ointment to the boy’s lip

Latin depends much more on case endings:

• mater tells you the subject
• unguentum tells you the direct object
• labro pueri tells you to the boy’s lip

So Latin can move words around more freely without changing the basic meaning. This sentence is perfectly normal Latin even though it does not follow the usual English order.

Yes, to a large extent. Because the endings show the grammatical roles, many rearrangements would still mean the same thing, for example:

• Mater unguentum labro pueri adhibet
• Mater labro pueri unguentum adhibet
• Unguentum mater labro pueri adhibet

The exact emphasis may change, but the core meaning stays the same because the forms still show:

• mater = subject
• unguentum = direct object
• labro pueri = to the boy’s lip

Adhibet is from adhibeo, adhibere, which can mean things like:

• apply
• put to
• bring to
• employ / use

Here it means applies.

Its form is:

• present tense
• active voice
• indicative mood
• 3rd person singular

So adhibet means he/she applies. With mater as the subject, it means the mother applies.

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

So:

• mater can mean mother, a mother, or the mother
• unguentum can mean ointment, an ointment, or the ointment

The exact choice in English depends on context and on what sounds natural in translation.