Mater dicit manus ante cenam sapone recte lavandas esse.

After dicit, Latin uses an indirect statement construction, often called the accusative-and-infinitive.

So the sentence breaks down like this:

• Mater dicit = Mother says
• manus ... lavandas esse = that hands must be washed

In this construction:

• the subject of the reported statement goes into the accusative
• the verb becomes an infinitive

So instead of a direct statement like:

• Manus ante cenam sapone recte lavandae sunt = Hands must be properly washed with soap before dinner

Latin reports it as:

• Mater dicit manus ante cenam sapone recte lavandas esse = Mother says that hands must be properly washed with soap before dinner

Because it is the subject of the indirect statement after dicit.

In English, we say Mother says that hands must be washed.
In Latin, the subject of that reported clause becomes accusative:

• manus = hands as the accusative subject of lavandas esse

This is very normal after verbs like:

• dico = say
• puto = think
• audio = hear
• scio = know

Here it is plural: hands.

That may look confusing, because manus is one of those forms that can look ambiguous in writing. The key is agreement:

• lavandas is feminine accusative plural
• therefore manus must also be feminine accusative plural

So here manus cannot mean hand; it has to mean hands.

Also, manus belongs to the fourth declension, and its forms are a little unusual compared with first- and second-declension nouns.

Because it agrees with manus.

The word lavandas is a gerundive from lavo, and gerundives behave like adjectives. That means they must match the noun they go with in:

• gender
• number
• case

Since manus here is:

• feminine
• plural
• accusative

the gerundive must also be:

• feminine
• plural
• accusative

So we get lavandas.

Lavandas esse means something like to have to be washed or must be washed.

This is the gerundive of obligation with esse, often called the passive periphrastic.

So:

• lavare = to wash
• lavari = to be washed
• lavanda esse / lavandas esse = to have to be washed, must be washed

In this sentence, the idea is not just that the hands are being washed, but that washing them is necessary or required.

Because the indirect statement needs an infinitive, and esse is part of the passive periphrastic expression.

In a direct statement, Latin would say:

• manus lavandae sunt = hands must be washed

But after dicit, the finite verb sunt changes into the infinitive esse:

• manus lavandas esse

So esse is not optional here; it is what turns the clause into the correct infinitive form for reported speech.

Because ante is a preposition that takes the accusative when it means before in time or space.

So:

• cena = dinner
• cenam = accusative singular
• ante cenam = before dinner

This is just the normal construction with ante.

Because Latin often uses the ablative of means or instrument without a preposition.

So:

• sapone = with soap, literally by means of soap

English usually wants with, but Latin does not need it here.

This is very common:

• gladio pugnat = he fights with a sword
• aqua lavat = he washes with water
• sapone lavandas esse = must be washed with soap

Recte means properly, correctly, or the right way.

It is an adverb, so it modifies the washing action:

• recte lavandas esse = must be washed properly

It is not describing soap or hands; it is describing how the washing should be done.

Latin often leaves out possessive words when they are obvious from the context.

So manus can simply mean:

• the hands
• one's hands
• your hands

depending on the situation.

In a sentence like this, spoken by a mother, the natural sense is often something like your hands must be properly washed with soap before dinner, even though Latin does not explicitly say tuas.

If Latin wanted to be more explicit, it could say manus tuas.

Not exactly.

The phrase lavandas esse tells us that the hands must be washed, but it does not explicitly name the person responsible.

Latin can express the person who has the obligation with a dative of agent, for example:

• tibi manus lavandae sunt = you must wash your hands / your hands must be washed by you

But in your sentence, no such dative is present. So the agent is left unstated and must be understood from context.

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

English depends heavily on word order to show who is doing what. Latin shows that mainly through endings, so the order can be rearranged more freely.

Here the order is:

• Mater dicit
• manus
• ante cenam
• sapone
• recte
• lavandas esse

That is perfectly natural Latin. The important relationships are shown by the forms:

• manus goes with lavandas
• cenam is accusative after ante
• sapone is ablative of means
• esse completes the indirect statement

So even though it feels less familiar to an English speaker, the endings make the structure clear.