Við prófum plötuspilarann þannig að kaupandinn heyrir hvernig hann virkar.

Prófum is the 1st person plural present form of prófa, meaning to test. So við prófum means we test or we are testing.

The ending -um is a very common present-tense ending for we in Icelandic verbs.

Because it is the direct object of prófum, so it appears in the accusative singular definite.

The basic noun is plötuspilari = record player / turntable. Its forms are:

• plötuspilari = nominative singular, indefinite
• plötuspilara = accusative singular, indefinite
• plötuspilarinn = nominative singular, definite
• plötuspilarann = accusative singular, definite

So Við prófum plötuspilarann means We test the record player.

Because kaupandinn is the subject of the subordinate clause, so it is in the nominative.

In other words:

• plötuspilarann = object of prófum → accusative
• kaupandinn = subject of heyrir → nominative

So the sentence changes case according to each noun’s job in the sentence.

Þannig að is a very common expression meaning something like so that, with the result that, or in such a way that.

Here it links the two parts:

• Við prófum plötuspilarann
• þannig að kaupandinn heyrir hvernig hann virkar

So it shows the result or intended effect of testing the record player.

Because this is a subordinate clause.

In main clauses, Icelandic often follows verb-second word order. But after a subordinating expression like að, the word order is usually more straightforward:

• subject + verb

So:

• kaupandinn heyrir
• hann virkar

That is normal subordinate-clause word order in Icelandic.

Because Icelandic pronouns follow grammatical gender, not just natural gender.

The noun plötuspilari is masculine, so when you refer back to it, you use hann.

So even though English would normally say it, Icelandic says hann because the noun is grammatically masculine.

Hvernig means how and introduces an embedded question:

• hvernig hann virkar = how it works

So the buyer hears how the record player works. Grammatically, this is not a direct question, but an indirect or embedded one.

Because the clause is being presented as a plain factual statement: the buyer hears how it works.

After hvernig, Icelandic very often uses the indicative when talking about something real and concrete. So:

• hvernig hann virkar = how it works

A subjunctive form would suggest a different nuance, such as uncertainty or a more dependent, less factual framing. That is not the point here.

In Icelandic, the simple present heyrir often covers what English might express as hears or can hear, depending on context.

So this sentence does not need a separate modal verb. The idea is that by testing the machine, the buyer gets to hear how it works.

That is a very natural use of the present tense in Icelandic.

Yes. Kaupandi comes from the verb kaupa = to buy and is historically a present participle form, literally something like buying one.

But in modern Icelandic it also functions as a normal noun meaning buyer. So kaupandinn simply means the buyer.

This is quite common in Icelandic: some -andi forms behave like ordinary nouns.

It can mean either, depending on context.

In many situations, plötuspilari is translated as record player. In some contexts, turntable may also fit well. Since the sentence is about testing the device so the buyer can hear it, either translation can make sense depending on what kind of equipment is meant.

Yes. Icelandic has several ways to express purpose or result. This sentence uses þannig að, which is very natural.

A learner may also meet expressions like til að or til þess að for in order to / so that. But the sentence you have is perfectly normal and emphasizes the practical result: they test it so the buyer hears how it works.