Mater filiam officiosam laudat, quia etiam cum lassa est, aviae et infanti auxilium fert.

The case endings tell you.

• mater is nominative singular, so it is the subject: the mother
• filiam is accusative singular, so it is the direct object: the daughter

So Mater filiam laudat means The mother praises the daughter.

In Latin, word order can change a lot, so you usually rely more on endings than on position.

Because officiosam is an adjective describing filiam, and Latin adjectives must agree with the nouns they describe in:

• gender
• number
• case

Here:

• filiam = feminine, singular, accusative
• officiosam = feminine, singular, accusative

So filiam officiosam means the dutiful/helpful daughter.

Because mater belongs to the third declension, not the first declension.

A learner often first meets many feminine nouns ending in -a, but not all feminine nouns do that.
mater is a very common third-declension noun:

• nominative: mater
• accusative: matrem
• genitive: matris

So mater is just the normal nominative singular form.

Officiosus, -a, -um can mean things like:

• dutiful
• obliging
• helpful
• attentive to duty

In this sentence, it suggests that the daughter is the kind of person who responsibly helps others. So officiosam fits well with the later idea that she brings help to her grandmother and the baby.

Latin often leaves out possessive words when the relationship is obvious from context.

So Mater filiam officiosam laudat naturally means The mother praises her dutiful daughter, even without an explicit her.

If Latin wanted to make it more explicit, it could use a possessive adjective, but it often does not need to.

Quia means because and introduces a clause giving the reason.

So the structure is:

• Mater filiam officiosam laudat = main clause
• quia ... auxilium fert = reason clause

In other words: the mother praises the daughter because she does this helpful action.

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

Latin cum can mean different things:

• with when used as a preposition + ablative noun
• when, since, or although when it introduces a clause

Here it is followed by a clause: lassa est
So cum lassa est means when she is tired.

Because of etiam, the whole phrase etiam cum lassa est means even when she is tired.

Because lassa is a predicate adjective with est, and predicate adjectives are in the nominative, not the accusative.

So:

• lassa est = she is tired

The adjective matches the understood subject of est:

• feminine
• singular
• nominative

That is why it is lassa, not lassam.

Grammatically, lassa est only tells you that the person is:

• feminine
• singular

So in isolation, it could refer to either mother or daughter.

But the most natural reading from the whole sentence is that it refers to the daughter. The logic is:

• the mother praises the daughter
• because the daughter, even when tired, brings help to others

So the sentence most likely means that the daughter is the one who is tired yet still helpful.

They are both in the dative case, because they are the people receiving the help.

• aviae = to/for the grandmother
• infanti = to/for the infant/baby

They depend on the expression auxilium fert.

So:

• aviae et infanti auxilium fert = she brings help to her grandmother and the baby

A common English-speaking learner question is why aviae ends in -ae, since that form can mean more than one thing. Here it is dative singular because the meaning requires to the grandmother, and it is parallel with infanti, which is clearly dative.

Yes, it is a common Latin way of expressing to bring help or to give help.

Literally:

• auxilium = help
• fert = carries / brings

But together auxilium ferre means:

• to bring help
• to offer assistance
• to help

So you should understand it as a normal Latin expression, not as if someone is physically carrying a thing called help.

Because Latin often leaves subject pronouns out when the verb ending already tells you the person and number.

• est = he/she/it is
• fert = he/she/it carries/brings

So Latin does not need to say ea for she unless it wants extra emphasis or contrast.

This is very normal in Latin.

The word order is meaningful, but not in the same rigid way as English.

Latin can move words around more freely because the endings show their grammatical roles. This sentence has a fairly natural order:

• Mater first, as the subject
• filiam officiosam together, since the adjective describes the noun
• laudat at the end of the main clause
• auxilium fert at the end of the reason clause

A few things to notice:

• putting officiosam after filiam is normal
• putting auxilium before fert keeps the object close to its verb
• the reason clause comes after the main clause, which is also very natural

So the order is flexible, but not random.

Because ferre is a very common verb in idiomatic expressions.

Its basic meaning is to carry or to bear, but in many phrases it extends beyond physical carrying.
With auxilium, the expression auxilium ferre is a standard way to say to help or to bring assistance.

So this is not strange Latin; it is exactly the kind of expression learners should get used to recognizing as a unit.

Here is a quick breakdown:

• Mater — nominative singular, feminine; subject
• filiam — accusative singular, feminine; direct object
• officiosam — accusative singular, feminine; adjective agreeing with filiam
• laudat — 3rd person singular present active; praises
• quia — conjunction; because
• etiam — adverb; even / also
• cum — conjunction here; when
• lassa — nominative singular, feminine; predicate adjective
• est — 3rd person singular present; is
• aviae — dative singular, feminine; to/for the grandmother
• et — and
• infanti — dative singular; to/for the infant
• auxilium — accusative singular, neuter; direct object of fert
• fert — 3rd person singular present active of ferre; brings

That full grammatical map is often helpful for seeing how the sentence fits together.