Apud aviam puella fabulam audit.

Because puella is in the nominative singular, which is the case normally used for the subject.

• puella = the girl as the doer of the action
• fabulam = the story as the thing being heard
• audit = he/she hears

So puella fabulam audit means the girl hears a story / the story.

Because fabulam is in the accusative singular, which is the case used for a direct object.

Here, the story is what the girl hears, so it must be in the accusative:

• fabula = a story as a subject
• fabulam = a story as a direct object

Compare:

• Fabula longa est = The story is long
• Puella fabulam audit = The girl hears the story / a story

No. aviam is not the direct object here. It is accusative because it follows the preposition apud.

Apud regularly takes the accusative case. So:

• avia = grandmother
• aviam = grandmother in the accusative, after apud

This is a very common thing in Latin: a noun can be accusative either because it is a direct object or because a preposition requires that case.

Here apud means something like:

• at the home of
• with
• in the company of
• sometimes more literally near or by

So apud aviam is best understood as at grandmother’s house or with grandmother, depending on the context.

Latin often expresses this idea differently from English. Instead of saying in grandmother’s house, Latin can simply say apud aviam.

Latin often prefers idioms that do not match English word-for-word.

With people, apud + accusative is very common for the idea of being at someone’s place or with someone. So:

• apud aviam = at grandmother’s house / with grandmother
• apud amicum = at a friend’s house / with a friend

A native English speaker may expect a word for house, but Latin does not always need one.

Latin word order is much freer than English word order because the case endings show the grammatical roles.

Putting the verb at the end is very common in Latin, especially in simple textbook sentences:

• Apud aviam puella fabulam audit

But Latin could also say:

• Puella apud aviam fabulam audit
• Puella fabulam audit apud aviam
• Fabulam puella apud aviam audit

These can all mean basically the same thing, though the emphasis may shift slightly.

You mainly know from the endings, not from the position.

In this sentence:

• puella = nominative singular → subject
• fabulam = accusative singular → direct object
• aviam = accusative singular after apud → object of the preposition
• audit = he/she hears

So even if the words moved around, the endings would still tell you the structure.

Audit is:

• present tense
• third person singular
• from the verb audio, audire = to hear

So audit means:

• he hears
• she hears
• it hears

Here, because the subject is puella, it means she hears.

Because Latin has no articles like English the and a/an.

So:

• puella can mean girl, a girl, or the girl
• fabulam can mean a story or the story
• aviam can mean grandmother or the grandmother

You decide from the context or from the translation already given.

Yes. Fabula has a range of meanings depending on context, including:

• story
• tale
• fable
• sometimes play or dramatic piece

In a simple sentence like this, story is usually the most natural translation.

A classroom-style pronunciation would be approximately:

• apud = AH-pood
• aviam = AH-wee-ahm

So the phrase sounds roughly like AH-pood AH-wee-ahm.

If you are using a restored classical pronunciation, the v sound is closer to w, which is why aviam is often pronounced roughly ah-wee-am.

Usually audio means hear rather than listen to.

So:

• puella fabulam audit = the girl hears a story

If you want a more deliberate sense like listen to, Latin often uses other expressions depending on context. But in beginner Latin, audio is normally best translated as hear.

Either order is possible. Latin often moves phrases around for emphasis, rhythm, or style.

Starting with apud aviam puts the location first:

• Apud aviam puella fabulam audit
  = At her grandmother’s place, the girl hears a story

Starting with puella would foreground the subject:

• Puella apud aviam fabulam audit
  = The girl, at her grandmother’s place, hears a story

Both are normal Latin.