Lucia signum parvum in margine ponit.

Lucia is the subject because it is in the nominative singular, the case normally used for the doer of the action. Also, ponit means he/she/it places, so the verb is singular and matches Lucia as a single subject.

Signum is the direct object, the thing being placed. It is in the accusative singular, which is the case Latin commonly uses for the direct object.

So in this sentence:

• Lucia = the one doing the action
• signum = the thing being placed

Because parvum has to agree with signum in gender, number, and case.

• signum is neuter
• singular
• accusative

So the adjective must also be neuter singular accusative: parvum

That is why you get signum parvum = a small sign/mark

Parvus would be masculine nominative singular, so it would not match signum.

In Latin, adjectives can come before or after the noun. Both are possible. So:

• signum parvum
• parvum signum

can both mean small sign/mark.

The version with the adjective after the noun is very normal Latin. Word order is often more flexible in Latin than in English because the endings show the grammar.

Because here in shows location, not motion toward.

• in + ablative = in/on a place
• in + accusative = into/onto a place

So:

• in margine = in the margin / on the margin
• in marginem would suggest movement into the margin

Since the sentence is describing where Lucia places the mark, Latin uses in margine, with margine in the ablative singular.

Margine is ablative singular.

Its dictionary form is margo, marginis and it means margin or edge.

So:

• nominative: margo
• ablative singular: margine

After in meaning in/on a place, the ablative is expected.

Ponit is:

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

It comes from the verb pono, ponere, meaning to place, to put, or to set.

So ponit means:

• he places
• she places
• it places

In this sentence, because the subject is Lucia, it means she places.

Classical Latin does not have articles like English a, an, or the.

So signum parvum could mean:

• a small mark
• the small mark

and in margine could mean:

• in a margin
• in the margin

The exact sense usually comes from the context.

Yes. Latin word order is flexible because grammatical roles are shown mostly by endings, not just by position.

For example, these could still mean roughly the same thing:

• Lucia signum parvum in margine ponit
• In margine Lucia signum parvum ponit
• Signum parvum Lucia in margine ponit

However, changing the order can change the emphasis. For instance, putting in margine first might emphasize the location.

Not always. Signum is a broad word. Depending on context, it can mean things like:

• sign
• mark
• symbol
• signal

In this sentence, if the meaning shown to the learner is something like small mark or small symbol, that fits the Latin well.

A simple classroom pronunciation would be:

LOO-kee-ah SIG-noom PAR-woom in MAR-gi-neh POH-nit

A few helpful points:

• c in Lucia is normally pronounced like k
• g in signum is always a hard g
• v in reconstructed classical pronunciation sounds like w, so parvum is closer to PAR-woom
• every written vowel is pronounced

Because it is the subject, and the subject is in the nominative case.

Lucia is a first-declension noun, and the nominative singular form is Lucia. If it had another job in the sentence, its ending might change. For example, if it were the direct object, you would expect Luciam instead.

Yes. It has everything needed for a complete sentence:

• Lucia = subject
• ponit = verb
• signum parvum = direct object
• in margine = prepositional phrase showing place

Latin often expresses ideas compactly, so short sentences like this are very normal.