Puer nomen proprium scribit.

Latin has no articles. That means a noun like puer can mean the boy or a boy, depending on context.

So:

• puer = the boy or a boy
• nomen proprium = the proper name or a proper name

English forces you to choose; Latin often does not.

Puer is in the nominative singular, the case normally used for the subject.

Also, the verb scribit is third person singular, so it matches a singular subject: he/she/it writes. Since puer means boy, the natural translation is the boy writes.

Here nomen proprium is the direct object, so it is accusative singular.

A beginner may expect the object to look obviously different, but here there is a special point:

• nomen is a neuter noun
• in Latin, neuter nominative and accusative are always identical

So nomen can be either nominative singular or accusative singular by form. In this sentence, it is accusative because it is the thing being written.

Because not all accusative singular nouns end in -m.

That is common in many first- and second-declension nouns, such as:

• puellam
• servum

But nomen is a third-declension neuter noun. Its accusative singular is simply nomen, the same as its nominative singular.

So nomen is accusative here even though it does not end in -m.

Because proprium describes nomen, not puer.

Latin adjectives must agree with the nouns they modify in:

• gender
• number
• case

Here:

• nomen is neuter
• singular
• accusative

So the adjective must also be neuter singular accusative:

• proprium

In this phrase, nomen proprium normally means proper name or proper noun.

That is an important point, because proprius can sometimes mean one’s own in other contexts. But with nomen, the phrase is commonly understood as proper name.

If you wanted to say his own name, Latin would more naturally use something like nomen suum.

Scribit is:

• present tense
• indicative mood
• active voice
• third person singular

It comes from scribere, meaning to write.

So scribit means:

• he writes
• she writes
• it writes

In this sentence, because the subject is puer, it means he writes.

Yes. The Latin present tense often covers both:

• writes
• is writing

So depending on context, puer nomen proprium scribit could be translated as either:

• The boy writes a proper name
• The boy is writing a proper name

English makes a stronger distinction than Latin does here.

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

So all of these could be possible Latin word orders:

• Puer nomen proprium scribit
• Nomen proprium puer scribit
• Scribit puer nomen proprium

The basic meaning stays the same, though the emphasis may shift.

The order in your sentence is a clear, straightforward textbook order.

Because puer belongs to a group of second-declension masculine nouns that end in -er instead of -us.

Compare:

• servus = slave
• puer = boy

Both are second declension, but they have different nominative endings.

The dictionary form is:

• puer, pueri

Unlike some -er nouns, puer keeps the e in the stem.

They are:

• puer, pueri = boy
• nomen, nominis = name
• proprius, propria, proprium = proper; one’s own
• scribo, scribere, scripsi, scriptum = write

Knowing the dictionary forms helps you see what declension or conjugation each word belongs to.

A simple Classical-style approximation is:

POO-er NOH-men proh-PREE-um SKREE-bit

A few helpful notes:

• puer has two syllables: pu-er
• c and g are always hard in Classical Latin
• v is pronounced like English w in Classical Latin, though there is no v in this sentence
• scribit begins with skr-, not sr-

If you are using an ecclesiastical pronunciation system, some details may differ.