Magister poetae iuveni consilium dat.

Because magister is in the nominative singular, which is the case normally used for the subject of the sentence.

In this sentence:

• magister = subject
• consilium = direct object, the thing being given
• poetae iuveni = indirect object, the person receiving it

So the endings tell you the grammatical roles, not just the word order.

Latin often does not need a separate word like to for an indirect object. It uses the dative case instead.

So poetae iuveni means to the young poet because both words are in the dative singular.

They go together. Iuveni is describing poetae and agrees with it in case, number, and gender.

So together they mean something like to the young poet.

A learner can treat iuveni here as being used adjectivally, even though its basic form is also very commonly a noun.

Because Latin agreement does not mean the endings must look identical. It means the words must match in case, number, and gender.

Here:

• poetae is dative singular from a first-declension word
• iuveni is dative singular from a third-declension word

Different declensions use different endings for the same case.

Yes. By itself, poetae could be:

• genitive singular = of the poet
• dative singular = to/for the poet
• nominative plural = poets

But in this sentence, dative singular is the best reading because:

• dat commonly takes a dative indirect object
• iuveni is also dative singular, so the two words clearly belong together

Yes, poeta is first declension, but first declension is not always feminine.

Some first-declension nouns referring to male people are masculine, especially words borrowed from Greek. Poeta is one of them.

Other common examples are:

• nauta = sailor
• agricola = farmer

So declension and gender are related, but they are not the same thing.

Because not all masculine second-declension nouns end in -us. Some end in -er.

So magister is still a normal masculine noun, just one of the -er type, like:

• puer
• ager
• liber

Its nominative singular simply happens to end differently.

Dat is third-person singular present active indicative of do, dare, dedi, datum.

So it means he gives, she gives, or it gives, depending on the subject. Here the subject is magister, so dat means the teacher gives.

Consilium is a neuter second-declension noun. In neuter nouns, the nominative and accusative forms are often identical.

So consilium can be either nominative singular or accusative singular in form. In this sentence, it is understood as accusative singular because it is the thing being given.

That is a very common Latin pattern:

• neuter nominative singular = neuter accusative singular

Latin word order is much more flexible than English word order because the endings already show the grammatical roles.

Putting the verb at the end is very common in Latin, but it is not required. This sentence has a very natural Latin order:

• subject first
• other elements in the middle
• verb last

A different order could still mean basically the same thing if the case endings stay the same.

Latin has no articles, so there is no separate word for the or a/an.

English has to add them when translating. Which one makes best sense depends on context.

So Latin magister can mean:

• the teacher
• a teacher

and consilium can mean:

• the advice
• advice
• a plan, depending on context

Not quite. The core meaning stays the same, but English may phrase it in different natural ways.

For example, depending on context, you might see:

• The teacher gives advice to the young poet.
• The teacher is giving advice to the young poet.
• A teacher gives advice to a young poet.

Latin often leaves details like the/a and sometimes aspect to be supplied by context.