Mater in foro nihil emit, quia panem nimium constare dicit.

Because in takes different cases depending on its meaning:

• in + ablative = in / on a place, with no motion
• in + accusative = into / onto a place, with motion toward it

So in foro means in the marketplace/forum. If the sentence meant into the forum, it would be in forum.

Nihil means nothing, and here it is the direct object of emit.

So the structure is:

• Mater = subject
• emit = verb
• nihil = object

Latin often says nihil emit for buys nothing, rather than using a separate negative with something.

Emit is 3rd person singular present active indicative of emo, emere, emi, emptum, meaning to buy.

So mater emit means mother buys or the mother buys.

A native English speaker may notice that emit looks like the English verb emit, but that is just a coincidence here. In this Latin sentence, emit comes from emo and means buys, not sends out.

Quia means because and introduces the reason for the main statement.

The sentence breaks down like this:

• Mater in foro nihil emit = the main statement
• quia panem nimium constare dicit = the reason why

So quia simply marks the because clause.

Because after verbs of saying, thinking, knowing, and similar verbs, Latin very often uses an indirect statement.

In English, we usually use a that-clause:

• She says that bread costs too much.

Latin usually does this differently:

• panem nimium constare dicit

That construction uses:

• an accusative noun for the subject of the reported statement
• an infinitive for the verb

So constare is infinitive because it is part of an indirect statement after dicit.

Logically, yes: bread is the thing that is doing the costing. But in Latin indirect statement, the subject of the reported clause goes into the accusative.

So:

• direct statement: panis nimium constat = bread costs too much
• indirect statement: panem nimium constare = that bread costs too much

That is why panem is accusative here instead of nominative panis.

There is no separate Latin word for that in this kind of sentence.

English says:

• she says that bread costs too much

Latin usually says:

• she says bread to cost too much

That sounds strange in English, but it is normal Latin grammar. The accusative-plus-infinitive construction does the job that English that does.

Here nimium is being used adverbially, meaning too much or excessively.

It modifies constare, so the sense is:

• to cost too much

So panem nimium constare means that bread costs too much.

It is not saying too much bread; it is saying that the bread is too expensive.

Latin word order is much more flexible than English word order because Latin uses case endings to show how words function.

English depends heavily on position:

• Mother buys nothing
• Nothing buys mother
  These mean different things because the order changes.

Latin can move words around more freely because the endings already show who is doing what. So this sentence could be arranged differently without changing the basic meaning, for example:

• Mater nihil in foro emit, quia dicit panem nimium constare.

The chosen order is still perfectly natural Latin.

By itself, mater just means mother. Latin has no word equivalent to English a/an or the.

So depending on context, it might be translated as:

• mother
• the mother
• sometimes even my mother

The English article or possessive has to be supplied from context.

Forum can mean a public square, forum, or marketplace. In a simple teaching sentence like this, in foro is usually best understood as in the market or in the marketplace.

So it probably refers to the place where buying and selling happens, not necessarily the famous Roman Forum in particular.

Both are present indicative forms.

In English, Latin present tense can often be translated in more than one way:

• buys / says
• sometimes is buying / is saying

In this sentence, the ordinary English translation is usually:

• Mother buys nothing in the market, because she says bread costs too much.

So the present tense here expresses a current or general situation.