Avia in cubili cubat, quia fessa est.

Avia is the subject of the sentence, so it is in the nominative singular. Its basic dictionary form is also avia, so here the nominative looks the same as the vocabulary form.

It comes first because Latin often puts the subject near the beginning, especially in simple sentences. But Latin word order is much freer than English word order, so avia does not have to come first to be understood as the subject.

Cubat means lies down, is lying, or rests reclining. It comes from the verb cubare.

A learner may wonder why Latin does not use a word meaning sleep here. The reason is that cubare focuses on being in a lying position, not necessarily sleeping. So the sentence is about where the grandmother is and what position she is in, not mainly about the act of sleeping.

Here in means in in the sense of location: where someone is.

When in means in/on with the idea of place where, it takes the ablative case. So cubili is ablative singular.

So:

• in cubili = in the bed / in the chamber / in the sleeping place
• in + ablative = location

By contrast, in + accusative usually shows motion into something.

Cubili is ablative singular.

You can tell this from two things:

• it follows in with the meaning of where
• the noun cubile is a third-declension neuter noun, and its ablative singular ends in -i

So the form fits exactly what we expect after in when it means location.

Quia means because. It introduces a clause that gives the reason:

• Avia in cubili cubat = the main statement
• quia fessa est = the reason

So quia begins a subordinate clause explaining why the grandmother is lying there.

Because fessa describes avia, and adjectives in Latin must agree with the nouns they describe.

Avia is:

• feminine
• singular
• nominative

So the adjective must also be:

• feminine
• singular
• nominative

That is why Latin uses fessa, not fessus.

Latin often uses an adjective with a form of sum (to be) just like English does:

• fessa est = she is tired

So est is the linking verb connecting the subject to the adjective.

Sometimes Latin can leave out est in certain styles, especially poetry or very compressed writing, but in normal straightforward prose it is perfectly natural to include it.

No. Even though the words appear in that order, you should understand them together as is tired.

Latin word order is more flexible than English word order. Very often the verb comes later, even at the end of the clause. So instead of translating word by word in English order, it is better to recognize the grammatical relationship:

• fessa = tired
• est = is

Together: is tired

Yes. Latin allows a lot of flexibility in word order, as long as the endings make the grammar clear.

For example, these would still mean essentially the same thing:

• Avia cubat in cubili, quia fessa est.
• In cubili avia cubat, quia fessa est.
• Avia in cubili, quia fessa est, cubat.

However, different word orders can change the emphasis. The original sentence is a natural, clear arrangement for a learner.

Yes. It is a complete subordinate clause.

It has:

• quia = because
• an understood subject = she (referring back to avia)
• fessa = tired
• est = is

So it is grammatically complete, even though the subject is not repeated.

Latin often leaves out subject pronouns when the verb already makes the person clear or when the subject is obvious from context.

In fessa est, the sentence does not need to repeat avia or add ea (she), because it is already clear that the clause is still talking about the grandmother.

This is very common in Latin and is something English speakers have to get used to, because English usually likes to repeat she.

Not exactly. They are related in meaning, but they are different nouns.

• cubile often means a bed, couch, resting place, or sleeping place
• cubiculum more often means a bedroom or chamber

So in cubili may suggest being in bed or in a resting place, not necessarily just in a room. The exact English wording depends on the context given to the learner.