Sed philosophus Graecus, qui prope stat, ridet et dicit multa adhuc difficilia esse.

Because together they form the subject of the main verbs ridet and dicit.

• philosophus = philosopher
• Graecus = Greek

Since Graecus describes philosophus, it must agree with it in case, number, and gender: masculine, singular, nominative.

Not really. Latin adjective placement is much freer than English word order.

So philosophus Graecus simply means Greek philosopher. Putting the adjective after the noun is very normal in Latin and usually does not change the basic meaning.

qui is a relative pronoun meaning who.

It refers back to philosophus Graecus, so it must match that antecedent in gender and number: masculine singular. It is nominative because it is the subject of stat.

So:

• philosophus Graecus = the Greek philosopher
• qui prope stat = who is standing nearby

Here prope is an adverb, meaning nearby or close by.

That is because it has no object after it.
Latin prope can also be a preposition meaning near, but then it would take an accusative noun, as in prope urbem = near the city.

Yes, stat literally means stands.

But in context, English often translates it more naturally as is standing. Latin present tense can cover both:

• simple present: stands
• progressive present: is standing

So qui prope stat can naturally mean who is standing nearby.

Because Latin usually uses an indirect statement after verbs like dicit.

Instead of saying:

• he says that many things are difficult

Latin says:

• he says many things to be difficult

That is why you get esse rather than sunt.

Direct statement:

• multa adhuc difficilia sunt = many things are still difficult

Indirect statement after dicit:

• dicit multa adhuc difficilia esse = he says that many things are still difficult

Yes. In the indirect statement, multa is the subject of esse.

However, in Latin indirect statement, that subject goes into the accusative, not the nominative. So multa is functioning as an accusative subject.

Because it is neuter plural.

In Latin, neuter plural nominative and accusative forms are identical. So multa can be either nominative plural or accusative plural depending on context.

Here the context shows it is accusative, because it is the subject of esse in an indirect statement after dicit.

Here multa means many things.

It is an adjective being used by itself, without an expressed noun. Latin does this often. The missing noun is understood as something like things.

So:

• multa = many things

Because it agrees with multa.

Since multa is neuter plural, difficilia must also be neuter plural. It is a predicate adjective with esse:

• multa ... difficilia esse = many things to be difficult

In natural English: that many things are difficult

adhuc means still, up to now, or as yet.

It goes with the idea difficilia esse, so the sense is:

• many things are still difficult

It tells you that the difficulty continues at this point.

Because Latin normally does not use a conjunction like English that in this construction.

English says:

• he says that many things are still difficult

Latin instead uses the accusative-and-infinitive pattern:

• dicit multa adhuc difficilia esse

So the whole infinitive phrase is the content of what he says.

It has three main parts:

1. Sed philosophus Graecus
   the main subject

2. qui prope stat
   a relative clause describing the philosopher

3. ridet et dicit multa adhuc difficilia esse
   the main verbs and the indirect statement after dicit

So the sentence is built like this:

• But the Greek philosopher
• who is standing nearby
• laughs and says that many things are still difficult