Ég verð óþolinmóður þegar tölvan virkar of hægt.

Because verða means to become / get, while vera means to be.

So:

• Ég er óþolinmóður = I am impatient
• Ég verð óþolinmóður = I become / get impatient

In this sentence, the idea is that the speaker starts to feel impatient when the computer is too slow, so verð is the natural choice.

Also, verð is the 1st person singular present tense of verða:

• ég verð = I become / get

Because it agrees with the speaker in gender, number, and case.

Here, óþolinmóður is an adjective describing ég. Icelandic adjectives change form depending on who or what they describe.

Óþolinmóður is the masculine singular nominative form.

So if a man is speaking, he would say:

• Ég verð óþolinmóður

A woman would normally say:

• Ég verð óþolinmóð

This is a very common feature of Icelandic: adjectives often have to match the noun or pronoun they describe.

The prefix ó- often means un-, in-, or im- in English. It gives the word a negative meaning.

So:

• þolinmóður = patient
• óþolinmóður = impatient

This is a useful pattern to notice, because ó- appears in many Icelandic words.

Because tölvan means the computer, while tölva means a computer / computer.

Icelandic usually puts the definite article onto the end of the noun instead of using a separate word like the.

So:

• tölva = computer / a computer
• tölvan = the computer

The noun tölva is feminine, and here -n (in the form -an) is the attached definite article.

Virkar is the 3rd person singular present tense of the verb virka.

Here tölvan is singular, so the verb is singular too:

• tölvan virkar = the computer works / functions

The verb virka often means to work in the sense of to function.

So in this sentence, virkar means that the computer is functioning, but doing so too slowly.

Because hægt is being used as an adverb, meaning slowly.

The word hægur is an adjective meaning slow, but Icelandic often uses the neuter singular form of an adjective as an adverb.

So:

• hægur = slow (masculine adjective form)
• hægt = slowly

That means:

• Tölvan er hæg = The computer is slow
• Tölvan virkar hægt = The computer works slowly

With of, it becomes:

• of hægt = too slowly

This is a very important Icelandic pattern.

Of means too.

So:

• hægt = slowly
• of hægt = too slowly

It is used when something is more than is acceptable or comfortable.

Compare:

• Tölvan virkar hægt = The computer works slowly
• Tölvan virkar of hægt = The computer works too slowly

Be careful not to confuse Icelandic of with English of. They are not the same word in meaning.

Þegar means when here.

It introduces a clause:

• þegar tölvan virkar of hægt = when the computer works too slowly

So the full sentence is built like this:

• Ég verð óþolinmóður = I get impatient
• þegar tölvan virkar of hægt = when the computer works too slowly

Together:

• Ég verð óþolinmóður þegar tölvan virkar of hægt.

If you put the þegar clause first, Icelandic changes the word order in the main clause:

• Þegar tölvan virkar of hægt, verð ég óþolinmóður.

Notice that verð comes before ég in that version. That is normal Icelandic word order after a fronted clause.

These two letters are very important in Icelandic.

• þ is pronounced like th in thing
• ð is pronounced like th in this

In this sentence:

• óþolinmóður has þ
• verð and hægt have ð

A rough guide:

• þ = voiceless th
• ð = voiced th, though in some positions it can sound weaker than in English

These sounds are one of the first pronunciation points English speakers usually need to practice in Icelandic.