Mater dicit sedecim nummos ad panem emendum satis esse.

Because this sentence uses indirect statement after dicit.

In Latin, after verbs of saying, thinking, knowing, and similar verbs, English often uses that + a finite verb:

• Mother says that sixteen coins are enough.

But Latin usually uses:

• accusative + infinitive

So sedecim nummos is the subject of the infinitive esse, and subjects of infinitives in this construction go into the accusative.

That is why Latin has:

• Mater dicit sedecim nummos ... satis esse.

not:

• Mater dicit sedecim nummi ...

Because it depends on dicit in an indirect statement.

A direct statement would be something like:

• Sedecim nummi satis sunt.
• Sixteen coins are enough.

But after Mater dicit = Mother says, Latin changes the finite verb into an infinitive:

• sedecim nummos satis esse
• literally, sixteen coins to be enough

So esse is not random; it is the normal Latin way of reporting a statement after dicit.

Because satis in Latin is usually an indeclinable adverb/neuter form meaning enough, sufficiently.

With esse, it often works almost like a predicate:

• satis est = it is enough
• nummos satis esse = that the coins are enough

It does not change form to match nummos. So Latin does not say something like sati nummi here.

Satis esse means to be enough.

In this sentence, the idea is:

• sedecim nummos ... satis esse
• that sixteen coins are enough

So the accusative noun phrase sedecim nummos is the logical subject, and satis esse is the predicate.

You can think of it as corresponding to a simple sentence:

• Sedecim nummi satis sunt.

Then after dicit, it becomes:

• sedecim nummos satis esse

This expresses purpose: for buying bread or to buy bread.

Latin often uses:

• ad
  • accusative

to express purpose, especially with a verbal noun/adjectival form. Here:

• ad = for, to
• panem = bread in the accusative
• emendum = buying / to be bought, agreeing with panem

So the phrase means:

• for buying bread
• more naturally in English, to buy bread

Emendum is a gerundive from emo, emere = to buy.

A gerundive is a verbal adjective. Here it agrees with panem:

• panem — masculine accusative singular
• emendum — masculine accusative singular

So literally panem emendum means something like bread to be bought. But in this construction with ad, the whole phrase means for buying bread.

Because Latin often prefers a gerundive construction when the verbal idea has a direct object.

Instead of using a gerund with an object:

• ad emendum panem

Classical Latin often prefers:

• ad panem emendum

This shifts the object panem into agreement with the gerundive emendum.

Both are understandable, but ad panem emendum is the more classically preferred style.

For two reasons working together:

1. It is governed by ad, which takes the accusative.
2. It is also the noun that emendum agrees with, so the gerundive must match it in case, number, and gender.

So:

• ad panem emendum
• for buying bread

with both words in the masculine accusative singular.

Because sedecim is an indeclinable numeral in Latin.

Many cardinal numbers from 11 to 17 do not change form for case, gender, or number. So whether the noun is nominative, accusative, or another case, sedecim stays the same.

That is why we get:

• sedecim nummos
• sedecim nummi

with sedecim unchanged while nummus changes form.

Nummos is the accusative plural of nummus.

It is plural because the number is sixteen, and it is accusative because, in indirect statement, the subject of the infinitive goes into the accusative.

So:

• direct statement: sedecim nummi satis sunt
• indirect statement: sedecim nummos satis esse

Because Latin word order is flexible, and placing Mater first gives the sentence a natural starting point: Mother says...

Latin often puts the main subject early, especially when introducing who is speaking or thinking. But other orders would also be possible, depending on emphasis.

So the order here is natural, but not the only grammatically possible one.

Latin very often puts the verb, especially an infinitive in indirect statement, toward the end of the clause.

So:

• Mater dicit sedecim nummos ad panem emendum satis esse.

is a very natural Latin order.

Putting esse at the end helps signal the completion of the reported statement. English does not usually wait so long for the verb, but Latin often does.

Yes. That would also be understandable and grammatical.

Latin word order is flexible, so the purpose phrase ad panem emendum can be placed in different positions. The version you have places it before satis esse, but moving it after esse or after satis would still make sense.

The given order may slightly emphasize the purpose before reaching the idea are enough.

No. Latin has several ways to express purpose, though this one is very common.

For example, Latin can sometimes use:

• a dative with satis in some contexts
• a purpose clause
• a gerund or gerundive phrase

But ad + gerundive is a straightforward and common way to say for buying bread / to buy bread, especially in textbook Latin.

It would be:

• Sedecim nummi ad panem emendum satis sunt.

That means:

• Sixteen coins are enough to buy bread.

This is useful because it shows the transformation into indirect statement:

• nummi → nummos
• sunt → esse

after Mater dicit.

Because Latin normally does not need that in indirect statement after verbs like dicit.

English says:

• Mother says that sixteen coins are enough.

Latin usually says:

• Mother says sixteen coins to be enough.

That is, Latin uses the accusative-and-infinitive construction instead of a conjunction like that plus a finite verb.

So there is no missing word here; the grammar itself expresses the reported statement.