Cum equa hinnit, infans ridet et ad ianuam currit.

No. Here cum is a conjunction, not a preposition.

• As a preposition, cum means with and is used with the ablative: for example, cum amico = with a friend.
• In this sentence, cum introduces a clause: Cum equa hinnit = When the mare neighs.

So here cum means when.

Because this is a straightforward temporal clause: when the mare neighs.

Latin uses cum with different moods depending on meaning:

• cum
  • indicative often gives a simple time meaning: when
• cum
  • subjunctive often gives background, causal, or circumstantial meaning: when/since/although

Here the sentence is just describing what happens when something happens, so hinnit is in the present indicative.

Because equa means mare, a female horse, while equus means horse or more specifically male horse/stallion in many contexts.

So the Latin is not just saying horse in a general way; it is specifically saying mare.

Grammatically, equa is:

• nominative singular
• first declension
• the subject of hinnit

Hinnit is:

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

It comes from the verb hinnire, meaning to neigh.

So hinnit means she neighs or it neighs, depending on context. Since the subject is equa, it means the mare neighs.

Infans means infant, baby, or child.

Here it is:

• nominative singular
• the subject of both ridet and currit

So infans ridet et ad ianuam currit means that the baby laughs and runs to the door.

A learner may notice that infans ends in -s, not -a or -us. That is because it is a third-declension noun, not a first- or second-declension one.

Because Latin commonly uses one subject for multiple verbs unless a new subject is introduced.

In this sentence:

• infans ridet = the baby laughs
• et ad ianuam currit = and runs to the door

There is no new noun given before currit, so the subject is still infans.

Also, both ridet and currit are 3rd person singular, which matches infans.

Ridet is:

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

It comes from ridere, meaning to laugh.

So infans ridet means the baby laughs.

Because ad + accusative is a very common way to show motion toward something.

• ad = to, toward
• ianuam is the accusative singular of ianua, meaning door

So ad ianuam currit means runs to the door.

If you used ianua by itself, that would be nominative and would not express the idea of motion toward the door in this sentence.

Ianuam is accusative singular.

That is because the preposition ad takes the accusative when it means to or toward.

So:

• ianua = nominative singular, door
• ianuam = accusative singular, used after ad

This is a standard pattern in Latin:

• ad villam = to the house
• ad urbem = to the city
• ad ianuam = to the door

Because Latin has no definite article and no indefinite article.

So Latin does not have separate words for:

• the
• a
• an

Whether a noun is translated as a mare, the mare, a baby, or the baby depends on the context.

That is why:

• equa can mean a mare or the mare
• infans can mean a baby or the baby

Not in the same rigid way as in English. Latin word order is fairly flexible because the endings show the grammatical roles.

This sentence is:

• Cum equa hinnit, infans ridet et ad ianuam currit.

But Latin could rearrange parts of it and still keep the same basic meaning, for example:

• Infans, cum equa hinnit, ridet et ad ianuam currit.
• Cum hinnit equa, infans ridet et ad ianuam currit.

The original order is natural and clear, but Latin relies more on endings than on fixed word order.

The sentence uses the present tense because it describes an action happening in the present or a repeated, typical action:

• hinnit = neighs
• ridet = laughs
• currit = runs

In a beginner sentence like this, the present often gives a simple sense such as:

• Whenever the mare neighs, the baby laughs and runs to the door or
• When the mare neighs, the baby laughs and runs to the door

The exact English translation can vary a little, but the Latin tense is straightforwardly present.

Et means and, and here it connects the two actions of the baby:

• ridet
• currit

So the structure is:

• infans ridet
• et
• ad ianuam currit

In other words, the baby does two things:

1. laughs
2. runs to the door

Yes, that is possible depending on context.

A present-tense temporal clause with cum can often sound like:

• when the mare neighs
• whenever the mare neighs

If the sentence describes a repeated situation, whenever may sound more natural in English. If it describes one event, when may sound more natural.

So both can be reasonable, depending on the situation imagined.

We know from the noun cases and verb endings.

• equa is nominative singular, so it is the subject of hinnit
• infans is nominative singular, so it is the subject of ridet and currit
• ianuam is accusative singular after ad, so it is the goal of motion, not the subject

And the verbs are all 3rd person singular:

• hinnit = he/she/it neighs
• ridet = he/she/it laughs
• currit = he/she/it runs

So the grammar makes the relationships clear.

A common classroom pronunciation would be roughly:

koom EH-kwa HIN-nit, IN-fahns RI-det et ad yah-NOO-am KOOR-rit

A few helpful notes:

• c is always hard, like k
• qu sounds like kw
• i in ianuam is like y at the start: ya-
• double consonants, like nn in hinnit, are pronounced more distinctly than in English if possible

Pronunciation varies somewhat depending on whether someone is using a more classical or more ecclesiastical system, but the grammar of the sentence stays the same.