Haec fabula ab illa differt.

Haec is the feminine nominative singular form of hic, haec, hoc (this).

It is feminine singular because it agrees with fabula, which is a feminine singular noun. Since fabula is the subject of the sentence, haec is also in the nominative.

So:

• haec = this
• fabula = story
• together, haec fabula = this story

A common beginner confusion is that haec can also be a neuter plural form in other contexts, but here the noun fabula makes the meaning and grammar clear.

Because fabula is the subject of the verb differt.

The sentence is about what this story does: it differs. In Latin, the subject is normally put in the nominative case.

So:

• fabula = nominative singular
• it is the thing doing the action of differing

Also, Latin does not use articles like the or a, so fabula can mean story, a story, or the story, depending on context.

Because the verb differre commonly expresses separation or distinction with ab + the ablative.

In English, we say:

• differs from that one

In Latin, that idea is often expressed as:

• ab illa differt = differs from that one

So ab illa means from that one or from that story.

Here illa is understood as referring to another feminine noun, most naturally fabula. Latin often leaves a repeated noun unstated when it is obvious.

So the full sense is:

• Haec fabula ab illa differt
  = This story differs from that one / from that story

Because it comes after ab, and ab takes the ablative case.

This is very important: some Latin forms look the same in more than one case. Illa can be:

• nominative feminine singular = that
• ablative feminine singular = by/with/from that

But once you see ab illa, the preposition tells you the case:

• ab
  • ablative

So here illa must be ablative feminine singular.

Both a and ab mean from and both are used with the ablative.

A common guideline is:

• ab is especially common before a vowel or h
• a is more common before a consonant

Since illa begins with a vowel sound, ab illa is the expected form.

So:

• ab illa = from that one

Differt is the 3rd person singular present active indicative of differre.

That means:

• present tense: it is happening now / generally true
• 3rd singular: he/she/it differs
• here the subject is haec fabula, so: this story differs

So differt means:

• differs
• or more literally, is different

No. They may look similar, but they are different words.

Here the verb is differre, and in this sentence it means to differ or to be different.

So:

• differt here = differs

A learner may be tempted to connect it with English defer, but that would be a different Latin verb: deferre.

So in this sentence, there is no idea of postponing or deferring. The meaning is specifically being different from.

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

This order is very natural:

• Haec fabula first: the topic, this story
• ab illa next: what it differs from
• differt last: the verb, which often comes near the end in Latin

But other orders are also possible, for example:

• Ab illa haec fabula differt
• Haec ab illa fabula differt would usually mean something slightly different unless carefully interpreted, so it is less straightforward

The original order is clear and idiomatic.

Because Latin often omits a noun when it is easily understood from context.

So instead of saying:

• Haec fabula ab illa fabula differt

Latin can simply say:

• Haec fabula ab illa differt

The feminine form illa already points to an understood feminine noun, and fabula is the obvious one.

This is very common in Latin and in English too:

• this story differs from that one

We do not need to repeat story in English either.