Puer voluntatem matris sequi debet.

Puer is the subject of the sentence, so it is in the nominative case.

• Dictionary form: puer, pueri = boy
• Here, puer means the boy or simply boy as the subject

Latin often uses the nominative for the person or thing doing the action.

Because voluntatem is the direct object of sequi.

• voluntas = nominative singular
• voluntatem = accusative singular

Since the boy is following the will, Latin puts voluntas into the accusative case: voluntatem.

Matris is genitive singular of mater, and it means of the mother or the mother’s.

So:

• voluntatem matris = the will of the mother
• or more naturally in English, the mother’s will

The genitive is commonly used to show possession or a close relationship between nouns.

Because sequi is the infinitive form, meaning to follow.

It appears here because Latin often uses:

• debet + infinitive = ought to / must + verb

So:

• debet sequi = ought to follow / must follow

Also, sequi comes from sequor, which is a deponent verb.

That means:

• it has passive-looking forms
• but an active meaning

So even though sequi looks unusual, it simply means to follow.

A deponent verb is a verb that uses passive forms but has an active meaning.

For example:

• sequor = I follow
• not I am followed

Its infinitive is sequi, which looks like a passive infinitive at first glance, but with deponent verbs that is normal.

So you should learn sequor, sequi as a unit and remember:

• form: passive-looking
• meaning: active

Because its subject, puer, is singular.

• puer = one boy
• debet = he ought / he must

If the subject were plural, the verb would also be plural:

• pueri ... debent = the boys ought to...

Latin verbs agree with their subjects in number and person.

Latin has no definite article like English the.

So puer can mean:

• boy
• the boy
• sometimes even a boy

The exact translation depends on the context. The same is true for voluntatem matris, which can be understood as the mother’s will even though there is no separate word for the.

Because Latin often does not add a possessive unless it is needed for clarity.

In this sentence, matris already tells you whose will it is: the mother’s. So there is no need for a separate word like his mother’s unless the context especially requires it.

If Latin wanted to emphasize his own mother, it could say something more explicit, but here matris is enough.

Yes. Latin word order is much more flexible than English word order because the case endings show each word’s job in the sentence.

So these could express basically the same idea:

• Puer voluntatem matris sequi debet.
• Puer debet voluntatem matris sequi.
• Voluntatem matris puer sequi debet.

The endings still show:

• puer = subject
• voluntatem = object
• matris = genitive
• debet = main finite verb
• sequi = infinitive

The chosen order may affect emphasis, but not the basic grammar.

Because matris is in the genitive, and genitives normally attach to a noun.

Here:

• voluntatem = will
• matris = of the mother

So the natural grouping is:

• [voluntatem matris] = the mother’s will

It would not make sense to connect matris directly with puer here, because the structure strongly points to matris describing voluntatem.

Here are the main dictionary forms:

• puer, pueri = boy
• voluntas, voluntatis = will, wish
• mater, matris = mother
• sequor, sequi, secutus sum = follow
• debeo, debere, debui, debitum = owe; ought; must

Knowing dictionary forms helps you identify:

• the base meaning
• the declension or conjugation
• how the word changes in different contexts

The main finite verb is debet.

That is the verb that is actually conjugated for person and number:

• debet = he/she/it ought or must

Sequi is an infinitive, so it depends on debet.

A good way to see the structure is:

• Puer = subject
• debet = main verb
• sequi = complementary infinitive
• voluntatem matris = object of sequi

So the core pattern is:

• The boy ought to follow ...