Puer sapone manus lavat.

The subject is puer.

You can tell because puer is in the nominative singular, the case normally used for the subject of a sentence. So puer means the boy or a boy, and it is the one doing the action.

Lavat is the verb. It is:

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

It comes from lavare, meaning to wash.

So lavat means he washes, she washes, or it washes. Here, because the subject is puer, it means the boy washes.

Here manus is accusative plural, so it means hands.

This can be confusing because manus is a 4th-declension noun, and its forms do not look like the more familiar 1st- or 2nd-declension patterns. With macrons, the form here would be written manūs.

So in this sentence:

• manus / manūs = hands
• it is the direct object, the thing being washed

Because it is in the accusative case, which is commonly used for the direct object.

The direct object answers the question what is being washed?

Answer: manus — the hands.

So:

• puer = the boy
• manus = hands
• lavat = washes

The boy washes his hands.

Sapone is in the ablative singular, and here it is an ablative of means or instrument.

That means it shows what means or what instrument is used to do the action.

So:

• sapone = with soap / by means of soap

Latin often uses the ablative by itself for this idea, without needing a separate word for with.

Because Latin often uses the bare ablative for means or instrument.

So when something is used as a tool or substance, Latin can simply put it in the ablative:

• sapone = with soap

You could think of it as using soap.

Cum is often used for with in the sense of together with someone or something, but for an instrument, the simple ablative is very common.

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

So puer ... manus lavat naturally means the boy washes his hands, not someone else’s hands.

Latin does not always need to say suas manus here, because that would usually be understood already.

Latin has no articles.

So puer can mean:

• the boy
• a boy

The exact English translation depends on context. The same is true for manus: it can be the hands or just hands, depending on how you translate it naturally.

The word order is somewhat flexible in Latin because the endings show what each word is doing.

So in Puer sapone manus lavat:

• puer is the subject
• manus is the object
• sapone shows means
• lavat is the verb

Even if the order changed, the basic meaning could stay the same. For example, Latin could also say:

• Puer manus sapone lavat
• Manus puer sapone lavat

The different orders can change emphasis, but the endings still tell you the grammar.

Latin very often puts the verb near or at the end of the sentence, although it does not have to.

So Puer sapone manus lavat has a very normal Latin feel. English usually prefers The boy washes his hands with soap, with the verb earlier, but Latin often saves the verb for last.

Yes, they are related.

Latin sapo, saponis means soap, and sapone is one of its case forms. English soap is historically related to that same word family.

So this is one of those nice cases where a Latin word looks familiar to an English speaker.