Geturðu bætt við þýðingu?

Because this is a yes/no question. In Icelandic, the finite verb usually comes first in that kind of question.

• Statement: Þú getur bætt við þýðingu. — You can add a translation.
• Question: Geturðu bætt við þýðingu? — Can you add a translation?

So the word order changes just like English changes you can to can you.

Geturðu is a very common contracted form of getur þú. It means exactly the same thing.

This kind of contraction happens a lot in everyday Icelandic, especially in questions:

• ertu = ert þú
• hefurðu = hefur þú
• geturðu = getur þú

So Geturðu bætt við þýðingu? and Getur þú bætt við þýðingu? mean the same thing, but the contracted form is very natural.

It comes from the verb geta, which means can / be able to.

Here are the most relevant forms:

• ég get — I can
• þú getur — you can
• hann/hún/það getur — he/she/it can

So geturðu is basically can you.

A useful warning for English speakers: geta does not mean English get.

The dictionary form of the verb is bæta, meaning to add. But after geta, Icelandic normally uses the supine form, which here is bætt.

So:

• bæta — dictionary form, to add
• bætt — the form used after geta here

That is why you get:

• Þú getur bætt ... — You can add ...

This is a pattern worth learning as a chunk: geta + supine.

Here við is part of the expression bæta við, which means to add or to add on.

So it is best to learn bæta við as a single unit rather than translating við by itself. In other contexts, við can mean things like with, against, or by, but here it is simply part of the verb phrase.

Because Icelandic nouns change form depending on their role in the sentence. The basic dictionary form is þýðing — translation, but in this sentence the noun appears in an oblique case form: þýðingu.

For learners, the main point is:

• þýðing — base form
• þýðingu — the form needed here after bæta við

So the -u ending is a normal case ending, not a different word.

Because Icelandic does not have an indefinite article like English a/an.

So a bare singular noun can mean:

• translation
• a translation

depending on context.

That is why þýðingu by itself can be understood as a translation.

Usually it works as a request, just like English Can you add a translation?

So even though it literally uses can, in normal use it often means something like:

• Can you add a translation?
• Could you add a translation?

It sounds natural and polite, not unusually formal.

You would say:

Þú getur bætt við þýðingu.

That means You can add a translation.

So the difference is mainly word order:

• Þú getur ... — statement
• Geturðu ... ? — question