Avia beneficium vicinae numquam obliviscitur et ei magnas gratias agit.

The sentence has one subject and two coordinated verbs:

• Avia = the subject, grandmother
• obliviscitur = first verb, forgets
• beneficium vicinae = what she does not forget, the neighbor’s kindness/favor
• et = and
• agit = second verb, gives/offers
• ei magnas gratias = great thanks to her

So the pattern is basically:

Subject + first verb + object + and + indirect object + second verb phrase

Latin does not always follow English word order, but the relationships are shown by the endings.

Because avia is in the nominative singular, the case normally used for the subject of a sentence.

• avia = grandmother
• ending -a here shows a first-declension nominative singular form

So avia is the one doing both actions:

• she does not forget
• she gives thanks

Because obliviscor, oblivisci, oblitus sum is a deponent verb.

A deponent verb:

• has passive-looking forms
• but an active meaning

So:

• obliviscitur looks like it could mean something passive
• but it actually means she forgets or she is forgetting

This is very common in Latin and often surprises English-speaking learners.

Obliviscitur is:

• 3rd person singular
• present indicative
• from obliviscor

So it means:

• she forgets
• or she is forgetting

In this sentence, with numquam, the sense is:

• she never forgets

Here beneficium is best understood as an accusative singular object: kindness, favor, or good deed.

A learner may notice that obliviscor is often taught with the genitive in Classical Latin. That is true: Classical authors often use a genitive after obliviscor. So a very classical-looking form might be something like beneficii instead of beneficium.

However:

• the accusative is also found
• and it is common in simpler or later Latin, and in some teaching materials

So in this sentence, beneficium functions as the thing that the grandmother does not forget.

Here vicinae is most naturally genitive singular:

• vicina = female neighbor
• vicinae = of the neighbor

So beneficium vicinae means:

• the neighbor’s kindness
• the favor of the neighbor

That is why vicinae is not the subject. It is modifying beneficium.

A common point of confusion is that vicinae could also be dative in another sentence, but here the meaning is clearly genitive: the neighbor’s.

Ei means to her here.

It is the dative singular of the pronoun is, ea, id.

In this sentence, it refers back to vicina:

• vicinae = of the neighbor
• ei = to her

So the grandmother:

• does not forget the neighbor’s kindness
• and gives thanks to her

Latin often uses a pronoun once the person has already been introduced.

So instead of repeating the noun, Latin can say:

• vicinae = of the neighbor
• then later ei = to her

This is very natural and avoids repetition. English does the same thing:

• the neighbor’s kindness ... and she thanks her

Because gratias agere is a fixed Latin idiom meaning to give thanks or to thank.

So Latin normally says:

• gratias agere alicui = to give thanks to someone

Here:

• gratias = accusative plural
• magnas agrees with it, so magnas gratias = great thanks

Even though English often says simply thanks or thank you, Latin commonly uses this plural expression.

Literally, it is something like:

• she does/gives great thanks

Idiomatic English is:

• she thanks her very much
• she gives her great thanks
• she is very grateful to her

Word by word:

• magnas = great, large
• gratias = thanks
• agit = does, drives, conducts, but in this idiom gives/offers

So gratias agere should really be learned as one phrase.

Because the subject is still avia.

Latin does not need to repeat the subject if it stays the same. Once avia has been named, the second verb agit automatically continues with the same subject unless something shows otherwise.

So:

• Avia ... obliviscitur
• et ... agit

means:

• The grandmother ... forgets
• and [the grandmother] gives thanks

English often does the same thing:

• The grandmother never forgets the kindness and thanks her

Because Classical Latin has no articles.

So:

• avia can mean a grandmother or the grandmother
• vicina can mean a neighbor or the neighbor
• beneficium can mean a kindness, the kindness, a favor, or the favor

Context tells you which English article makes the most sense. In this sentence, English naturally uses the:

• The grandmother never forgets the neighbor’s kindness...

Latin word order is fairly flexible because the endings show the grammatical roles.

So the exact order here is natural, but not the only possibility. The sentence puts things in a clear flow:

• Avia first: the topic or subject
• beneficium vicinae before obliviscitur: what she never forgets
• numquam near obliviscitur: emphasis on never
• ei before magnas gratias agit: making the recipient of the thanks clear

A different order could still make sense if the case endings stayed the same. In Latin, changing word order often changes emphasis, not the basic grammar.