Leikarinn og leikstjórinn ræða frammistöðuna.

They are:

• leikari = actor
• leikstjóri = director
• ræða = to discuss
• frammistaða = performance

In the sentence, these words appear in inflected forms:

• leikarinn
• leikstjórinn
• ræða
• frammistöðuna

Because Icelandic usually adds the definite article to the end of the noun instead of using a separate word like English the.

So:

• leikari = actor
• leikarinn = the actor

and

• leikstjóri = director
• leikstjórinn = the director

Here, -inn is the definite ending for these masculine singular nouns in the nominative.

Because frammistöðuna is not the basic form. It is the accusative singular definite form.

The dictionary form is:

• frammistaða = performance

But after the verb ræða, the noun is used as a direct object, so it goes into the accusative:

• frammistöðu = performance (accusative, indefinite)
• frammistöðuna = the performance (accusative, definite)

So there are two things happening:

1. the noun changes form because of case
2. the definite article is added at the end

• Leikarinn = nominative
• leikstjórinn = nominative
• frammistöðuna = accusative

The first two are in the nominative because they are the subject of the sentence: they are doing the action.

Frammistöðuna is in the accusative because it is the direct object of ræða.

Because the subject is plural in meaning:

• Leikarinn og leikstjórinn = the actor and the director

That means two people, so the verb must be 3rd person plural.

Compare:

• Leikarinn ræðir frammistöðuna. = The actor discusses the performance.
• Leikarinn og leikstjórinn ræða frammistöðuna. = The actor and the director discuss the performance.

So:

• ræðir = singular
• ræða = plural

That is a very good question, because the infinitive and the 3rd person plural present can look the same.

Here, ræða is clearly a finite verb because:

• it comes after the subject
• it completes the sentence as the main verb
• there is no að, which often introduces the infinitive

So here:

• Leikarinn og leikstjórinn ræða frammistöðuna.

means The actor and the director discuss the performance, not the actor and the director to discuss the performance.

Yes. In this sentence, ræða takes a direct object in the accusative.

So:

• ræða eitthvað = to discuss something

That is why we get:

• frammistöðuna and not the nominative form frammistaðan

This is something you often just have to learn with the verb: which case it governs.

Because Icelandic ræða can take the thing being discussed directly as its object.

So Icelandic works like English discuss:

• ræða frammistöðuna = discuss the performance

You do not need a preposition here.

That is different from verbs that work more like English talk about.

Because both nouns are definite:

• the actor
• the director

In Icelandic, that usually means each noun carries its own definite article:

• leikarinn og leikstjórinn

This is very natural Icelandic. Each noun is separately marked as the noun.

Yes. This is the neutral, straightforward order:

• subject + verb + object

So:

• Leikarinn og leikstjórinn = subject
• ræða = verb
• frammistöðuna = object

Icelandic word order can change for emphasis or because of the verb-second pattern, but this sentence is the most ordinary and learner-friendly structure.

Yes. They both begin with leik-, which is related to play / acting / performance.

• leikari = actor
• leikstjóri = director

This is useful because Icelandic often builds vocabulary through compounds. If you learn common parts like leik- and -stjóri, new words become easier to recognize.

A few helpful points:

• æ in ræða is roughly like the vowel in English eye
• ð is like the th in this (though in real speech it can be softer)
• ö in frammistöðuna does not sound like English o; it is closer to German ö or French eu
• ll in Leikarinn is just a normal l sound here

A rough pronunciation guide for an English speaker might be:

• Leikarinn ≈ LAY-ka-rinn
• leikstjórinn ≈ LAYK-styoh-rinn
• ræða ≈ RYE-tha
• frammistöðuna ≈ FRAM-mi-stur-thu-na

That is only approximate, but it helps you notice the main sound differences.