Mater valde gaudet, quia filia veritatem dicit.

Because mater is the subject of the main clause, so it is in the nominative case.

• mater = mother as the one doing the action
• gaudet = is glad / rejoices

If mother were the direct object, then a different case would be used.

Latin usually does not use articles.

So:

• mater can mean mother, a mother, or the mother
• filia can mean daughter, a daughter, or the daughter
• veritatem can mean truth, the truth, or sometimes a truth, depending on context

English requires articles much more often than Latin does.

Gaudet is the 3rd person singular present active indicative of gaudēre, meaning to rejoice, to be glad, or to be happy.

So gaudet means:

• she is glad
• she rejoices

The -t ending tells you the subject is he/she/it.

Valde is an adverb meaning very, greatly, or strongly.

It modifies gaudet, so:

• gaudet = is glad
• valde gaudet = is very glad

A learner may expect very to go with adjectives only, but in Latin valde can intensify verbs too.

Yes. Latin word order is more flexible than English word order.

Both of these are possible:

• Mater valde gaudet
• Mater gaudet valde

The version with valde before gaudet is very natural, but changing the order can slightly change emphasis.

Quia means because and introduces a clause giving a reason.

So the sentence is divided like this:

• main clause: Mater valde gaudet
• reason clause: quia filia veritatem dicit

It tells us why the mother is glad.

Because filia is the subject of the clause after quia.

In filia veritatem dicit:

• filia = the daughter, the one doing the speaking
• veritatem = the truth, the thing being spoken

Since filia is the subject, it is nominative.

Because it is the direct object of dicit.

In other words, it answers the question what does the daughter say?

• filia = subject
• dicit = says
• veritatem = object

The dictionary form is veritas, but here the accusative singular is veritatem.

It comes from veritas, veritatis, a 3rd-declension noun meaning truth.

Its forms include:

• nominative singular: veritas
• accusative singular: veritatem

So when it is used as a direct object, Latin uses veritatem.

Dicit is the 3rd person singular present active indicative of dicere, meaning to say or to speak.

So filia veritatem dicit means:

• the daughter says the truth
• more naturally in English: the daughter tells the truth

Again, the -t ending shows he/she/it.

Because Latin verb endings already show the person and number.

For example:

• gaudet = she/he/it is glad
• dicit = she/he/it says

Since the endings already tell you that the verb is 3rd person singular, Latin often leaves the pronoun unstated unless it is needed for emphasis or clarity.

Because this sentence presents the reason as a straightforward fact:

• quia filia veritatem dicit = because the daughter tells the truth

With quia, Latin commonly uses the indicative when the reason is stated as real or factual. A learner may later meet more complicated cases, but here the indicative is the normal choice.

Yes, to a large extent. Latin relies heavily on endings, so word order is more flexible than in English.

Possible rearrangements include:

• Quia filia veritatem dicit, mater valde gaudet.
• Mater, quia filia veritatem dicit, valde gaudet.
• Veritatem filia dicit, quia mater valde gaudet. would change the sense and emphasis, so not every rearrangement is equally good

The original sentence is straightforward and natural, but Latin often moves words around for emphasis, style, or rhythm.