Miles de familia sua saepe cogitat.

Miles is in the nominative singular, which is the case normally used for the subject of a Latin sentence.

• miles = soldier
• nominative singular of a 3rd-declension noun

So Miles ... cogitat means The soldier ... thinks or A soldier ... thinks.

Latin often shows the job of a word by its ending, not by putting it first in the sentence.

After de, Latin normally uses the ablative case. So familia here is ablative singular.

• dictionary form: familia
• ablative singular: also familia

The phrase de familia means about the family or concerning the family.

This is important because cogitare de + ablative is a very common way to say to think about something.

Because the idea is think about, and in Latin that is commonly expressed as:

cogitare de + ablative

So:

• cogitat de familia = he/she thinks about the family

English uses about, while Latin uses de with the ablative.

Sua is a reflexive possessive adjective. It refers back to the subject of the sentence.

So in this sentence:

• Miles de familia sua saepe cogitat.

sua means his own (or her own, depending on context), because it refers back to miles, the subject.

If Latin used eius instead, that would usually mean his/her family belonging to someone else, not to the subject.

So:

• familia sua = his own family
• familia eius = someone else’s family

Sua agrees with familia, not with the person who possesses it.

That means it matches familia in:

• gender: feminine
• number: singular
• case: ablative

So we get:

• familia = feminine singular ablative
• sua = feminine singular ablative

Even though sua refers back to the soldier, its form is chosen to match familia.

Cogitat is:

• 3rd person singular
• present tense
• active voice
• indicative mood

It comes from the verb cogitare, meaning to think.

Because the subject miles is singular, the verb is also singular:

• miles cogitat = the soldier thinks

If the subject were plural, the verb would change:

• milites cogitant = the soldiers think

Saepe is an adverb, meaning often.

It modifies the verb cogitat, telling us how often the soldier thinks about his family.

So the sense is:

• he often thinks

Adverbs in Latin are fairly flexible in position, so saepe could appear in different places without changing the basic meaning.

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

So all of these would mean roughly the same thing:

• Miles de familia sua saepe cogitat.
• Miles saepe de familia sua cogitat.
• De familia sua miles saepe cogitat.
• Saepe miles de familia sua cogitat.

The differences are mainly in emphasis or style, not basic meaning.

In the original sentence, the verb comes at the end, which is very common in Latin.

Latin does not have articles like English the and a/an.

So miles can mean:

• the soldier
• a soldier

And familia can mean:

• the family
• a family

Which one sounds best depends on the context. Latin leaves that for the reader to infer.

Not always exactly.

Familia can mean family, but in Roman usage it can also have a broader sense, such as a household. Depending on context, it might include not just close relatives but the whole domestic group.

In a beginner sentence like this, family is usually the best understanding, but it is good to know the Latin word can be a little broader than the modern English one.