Mater puerum monet ut manus sordidas ante ientaculum lavet.

It has two parts:

• Main clause: Mater puerum monet = The mother warns/advises the boy
• Subordinate clause: ut manus sordidas ante ientaculum lavet = that he should wash his dirty hands before breakfast

So the structure is:

mother + warns/advises + boy + that he should wash...

Latin often uses this kind of ut + subjunctive clause after verbs of advising, urging, warning, and commanding.

Because puerum is the direct object of monet.

The verb moneo, monere can mean warn, advise, or remind, and the person being warned/advised is put in the accusative:

• mater puerum monet = the mother warns/advises the boy

Even though the boy is also the one who is supposed to do the washing, Latin does not need to repeat him as the subject of lavet. It is understood from the context.

Here ut introduces a clause meaning that or so that, but after a verb like monet it is often best translated in English as to or that he should:

• monet ut lavet = advises/warns him to wash
• literally, warns/advises that he should wash

So this is not just any ut clause; it is the kind used after verbs of urging, advising, or commanding.

Because after monet ut, Latin uses the subjunctive, not the indicative.

• lavat = he washes / is washing (indicative)
• lavet = he should wash / may wash (subjunctive)

So ut ... lavet fits the idea of advice or instruction.

In other words:

• monet ut lavet = she advises him to wash
• not she says that he washes

Lavet is:

• present
• subjunctive
• active
• third person singular

from lavo, lavare = to wash

It is third person singular because the understood subject is the boy.

Here it means hands.

The noun manus is a fourth-declension noun, and some of its singular and plural forms can look the same when written without macrons. In this sentence, we know it is plural because of the adjective sordidas, which is clearly accusative plural.

So:

• manus sordidas = dirty hands

not dirty hand

Because it agrees with manus.

Latin adjectives must agree with the nouns they describe in:

• gender
• number
• case

Here:

• manus is feminine
• it is accusative plural
• so the adjective must also be feminine accusative plural

That gives:

• manus sordidas = dirty hands

Latin often leaves out possessive words like his, her, or their when the possessor is obvious from the context, especially with body parts.

So manus sordidas naturally means his dirty hands here, because the boy is the one being told to wash them.

If Latin wanted to emphasize his own hands, it could say something like manus suas sordidas, but that is not necessary here.

Because ante is a preposition that takes the accusative.

• ante = before
• ientaculum = breakfast

So:

• ante ientaculum = before breakfast

This is a normal prepositional phrase in Latin.

Yes. Latin word order is much freer than English word order because the endings show the grammatical relationships.

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

• Mater monet puerum ut manus sordidas ante ientaculum lavet.
• Puerum mater monet ut manus sordidas ante ientaculum lavet.

The given order is perfectly natural, but Latin does not rely on word order as strictly as English does.

Because Latin and English build this idea differently.

English often says:

• The mother advises the boy to wash his hands

Latin commonly uses:

• mater puerum monet ut ... lavet
• literally, the mother advises the boy that he should wash...

So Latin prefers a full subordinate clause here, with ut and the subjunctive, rather than copying the English infinitive structure.

It can mean any of those, depending on context.

The verb moneo has a range of meanings such as:

• warn
• advise
• remind

In this sentence, since the mother is telling the boy to wash his hands before breakfast, advises or warns both make sense. The exact English choice depends on the tone the translator wants.